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[Federal Register Volume 80, Number 124 (Monday, June 29, 2015)]
[Unknown Section]
[Pages 37053-37127]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-13435]

[[Page 37053]]

Vol. 80

Monday,

No. 124

June 29, 2015

Part II

Department of Defense

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Department of the Army, Corps of Engineers

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33 CFR Part 328

Environmental Protection Agency

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40 CFR Parts 110, 112, 116, et al.

Clean Water Rule: Definition of ``Waters of the United States''; Final 
Rule

Federal Register / Vol. 80 , No. 124 / Monday, June 29, 2015 / 
Rules

[[Page 37054]]

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DEPARTMENT OF DEFENSE

Department of the Army, Corps of Engineers

33 CFR Part 328

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 110, 112, 116, 117, 122, 230, 232, 300, 302, and 401

[EPA-HQ-OW-2011-0880; FRL-9927-20-OW]
RIN 2040-AF30

Clean Water Rule: Definition of ``Waters of the United States''

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

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) and the U.S. Army 
Corps of Engineers (Corps) are publishing a final rule defining the 
scope of waters protected under the Clean Water Act (CWA or the Act), 
in light of the statute, science, Supreme Court decisions in U.S. v. 
Riverside Bayview Homes, Solid Waste Agency of Northern Cook County v. 
U.S. Army Corps of Engineers (SWANCC), and Rapanos v. United States 
(Rapanos), and the agencies' experience and technical expertise. This 
final rule reflects consideration of the extensive public comments 
received on the proposed rule. The rule will ensure protection for the 
nation's public health and aquatic resources, and increase CWA program 
predictability and consistency by clarifying the scope of ``waters of 
the United States'' protected under the Act.

DATES: This rule is effective on August 28, 2015. In accordance with 40 
CFR part 23, this regulation shall be considered issued for purposes of 
judicial review at 1 p.m. Eastern time on July 13, 2015.

FOR FURTHER INFORMATION CONTACT: Ms. Donna Downing, Office of Water 
(4502-T), Environmental Protection Agency, 1200 Pennsylvania Avenue 
NW., Washington, DC 20460; telephone number 202-566-2428; email 
address: CWAwaters@epa.go v. Ms. Stacey Jensen, Regulatory Community of 
Practice (CECW-CO-R), U.S. Army Corps of Engineers, 441 G Street NW., 
Washington, DC 20314; telephone number 202-761-5856; email address: 
USACE_CWA_Rule@usace.army.mil.

SUPPLEMENTARY INFORMATION: This final rule does not establish any 
regulatory requirements. Instead, it is a definitional rule that 
clarifies the scope of ``waters of the United States'' consistent with 
the Clean Water Act (CWA), Supreme Court precedent, and science. 
Programs established by the CWA, such as the section 402 National 
Pollutant Discharge Elimination System (NPDES) permit program, the 
section 404 permit program for discharge of dredged or fill material, 
and the section 311 oil spill prevention and response programs, all 
rely on the definition of ``waters of the United States.'' Entities 
currently are, and will continue to be, regulated under these programs 
that protect ``waters of the United States'' from pollution and 
destruction.
    State, tribal, and local governments have well-defined and 
longstanding relationships with the Federal government in implementing 
CWA programs and these relationships are not altered by the final rule. 
Forty-six states and the U.S. Virgin Islands have been authorized by 
EPA to administer the NPDES program under section 402, and two states 
have been authorized by the EPA to administer the section 404 program. 
All states and forty tribes have developed water quality standards 
under the CWA for waters within their boundaries. A federal advisory 
committee has recently been announced to assist states in identifying 
the scope of waters assumable under the section 404 program.
    The scope of jurisdiction in this rule is narrower than that under 
the existing regulation. Fewer waters will be defined as ``waters of 
the United States'' under the rule than under the existing regulations, 
in part because the rule puts important qualifiers on some existing 
categories such as tributaries. In addition, the rule provides greater 
clarity regarding which waters are subject to CWA jurisdiction, 
reducing the instances in which permitting authorities, including the 
states and tribes with authorized section 402 and 404 CWA permitting 
programs, would need to make jurisdictional determinations on a case-
specific basis.

Table of Contents

I. General Information
    A. How can I get copies of this document and related 
information?
    B. Under what legal authority is this rule issued?
II. Executive Summary
III. Significant Nexus Determinations
    A. The Significant Nexus Standard
    B. Science Report
    C. Significant Nexus Conclusions
    1. Scope of Significant Nexus Analysis
    2. Categories of Waters Determined to Have a Significant Nexus
    3. Case-Specific Significant Nexus Determinations
IV. Definition of ``Waters of the United States''
    A. Summary of Rule
    B. Traditional Navigable Waters
    C. Interstate Waters
    D. Territorial Seas
    E. Impoundments
    F. Tributaries
    G. Adjacent Waters
    H. Case-Specific ``Waters of the United States''
    I. Waters and Features That Are Not ``Waters of the United 
States''
V. Economic Impacts
VI. Related Acts of Congress, Executive Orders, and Agency 
Initiatives
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    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
    K. Congressional Review Act
    L. Environmental Documentation
    M. Judicial Review

I. General Information

A. How can I get copies of this document and related information?

    1. Docket. An official public docket for this action has been 
established under Docket Id. No. EPA-HQ-OW-2011-0880. The official 
public docket consists of the documents specifically referenced in this 
action, any public comments received, and other information related to 
this action. The official public docket also includes a Technical 
Support Document that provides additional legal and scientific 
discussion for issues raised in this rule, and the Response to Comments 
document. Although a part of the official docket, the public docket 
does not include Confidential Business Information or other information 
whose disclosure is restricted by statute. The official public docket 
is the collection of materials that is available for public viewing at 
the OW Docket, EPA West, Room 3334, 1301 Constitution Ave. NW., 
Washington, DC 20004. This Docket Facility is open from 8:30 a.m.

[[Page 37055]]

to 4:30 p.m., Monday through Friday, excluding legal holidays. The OW 
Docket telephone number is 202-566-2426. A reasonable fee will be 
charged for copies.
    2. Electronic Access. You may access this Federal Register document 
electronically under the ``Federal Register'' listings at http://www.regulations.gov. An electronic version of the public docket is 
available through EPA's electronic public docket and comment system, 
EPA Dockets. You may access EPA Dockets at http://www.regulations.gov 
to view public comments, access the index listing of the contents of 
the official public docket, and access those documents in the public 
docket that are available electronically. For additional information 
about EPA's public docket, visit the EPA Docket Center homepage at 
http://www.epa.gov/epahome/dockets.htm. Although not all docket 
materials may be available electronically, you may still access any of 
the publicly available docket materials through the Docket Facility.

B. Under what legal authority is this rule issued?

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

II. Executive Summary

    In this final rule, the agencies clarify the scope of ``waters of 
the United States'' that are protected under the Clean Water Act (CWA), 
based upon the text of the statute, Supreme Court decisions, the best 
available peer-reviewed science, public input, and the agencies' 
technical expertise and experience in implementing the statute. This 
rule makes the process of identifying waters \1\ protected under the 
CWA easier to understand, more predictable, and consistent with the law 
and peer-reviewed science, while protecting the streams and wetlands 
that form the foundation of our nation's water resources.
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    \1\ The agencies use the term ``water'' and ``waters'' in 
categorical reference to rivers, streams, ditches, wetlands, ponds, 
lakes, oxbows, and other types of natural or man-made aquatic 
systems, identifiable by the water contained in these aquatic 
systems or by their chemical, physical, and biological indicators. 
The agencies use the terms ``waters'' and ``water bodies'' 
interchangeably in this preamble.
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    Congress enacted the CWA ``to restore and maintain the chemical, 
physical, and biological integrity of the Nation's waters,'' section 
101(a), and to complement statutes that protect the navigability of 
waters, such as the Rivers and Harbors Act. 33 U.S.C. 401, 403, 404, 
407. The CWA is the nation's single most important statute for 
protecting America's clean water against pollution, degradation, and 
destruction. To provide that protection, the Supreme Court has 
consistently agreed that the geographic scope of the CWA reaches beyond 
waters that are navigable in fact. Peer-reviewed science and practical 
experience demonstrate that upstream waters, including headwaters and 
wetlands, significantly affect the chemical, physical, and biological 
integrity of downstream waters by playing a crucial role in controlling 
sediment, filtering pollutants, reducing flooding, providing habitat 
for fish and other aquatic wildlife, and many other vital chemical, 
physical, and biological processes.
    This final rule interprets the CWA to cover those waters that 
require protection in order to restore and maintain the chemical, 
physical, or biological integrity of traditional navigable waters, 
interstate waters, and the territorial seas. This interpretation is 
based not only on legal precedent and the best available peer-reviewed 
science, but also on the agencies' technical expertise and extensive 
experience in implementing the CWA over the past four decades. The rule 
will clarify and simplify implementation of the CWA consistent with its 
purposes through clearer definitions and increased use of bright-line 
boundaries to establish waters that are jurisdictional by rule and 
limit the need for case-specific analysis. The agencies emphasize that, 
while the CWA establishes permitting requirements for covered waters to 
ensure protection of water quality, these requirements only apply with 
respect to discharges of pollutants to the covered water. In the 
absence of a discharge of a pollutant, the CWA does not impose 
permitting restrictions on the use of such water.
    Additionally, Congress has exempted certain discharges, and the 
rule does not affect any of the exemptions from CWA section 404 
permitting requirements provided by CWA section 404(f), including those 
for normal farming, ranching, and silviculture activities. CWA section 
404(f); 40 CFR 232.3; 33 CFR 323.4. This rule not only maintains 
current statutory exemptions, it expands regulatory exclusions from the 
definition of ``waters of the United States'' to make it clear that 
this rule does not add any additional permitting requirements on 
agriculture. The rule also does not regulate shallow subsurface 
connections nor any type of groundwater, erosional features, or land 
use, nor does it affect either the existing statutory or regulatory 
exemptions from NPDES permitting requirements, such as for agricultural 
stormwater discharges and return flows from irrigated agriculture, or 
the status of water transfers. CWA section 402(l)(1); CWA section 
402(l)(2); CWA section 502(14); 40 CFR 122.3(f); 40 CFR 122.2.
    Finally, even where waters are covered by the CWA, the agencies 
have adopted many streamlined regulatory requirements to simplify and 
expedite compliance through the use of measures such as general permits 
and standardized mitigation measures. The agencies will continue to 
develop general permits and simplified procedures, particularly as they 
affect crossings of covered ephemeral and intermittent tributaries 
jurisdictional under this rule to ensure that projects that offer 
significant social benefits, such as renewable energy development, can 
proceed with the necessary environmental safeguards while minimizing 
permitting delays.
    The jurisdictional scope of the CWA is ``navigable waters,'' 
defined in section 502(7) of the statute as ``waters of the United 
States, including the territorial seas.'' The term ``navigable waters'' 
is used in a number of provisions of the CWA, including the section 402 
National Pollutant Discharge Elimination System (NPDES) permit program, 
the section 404 permit program, the section 311 oil spill prevention 
and response program,\2\ the water quality standards and total maximum 
daily load programs (TMDL) under section 303, and the section 401 state 
water quality certification process. However, while there is only one 
CWA definition of ``waters of the United States,'' there may be other 
statutory factors that define the reach of a particular CWA program or 
provision.\3\

[[Page 37056]]

Existing regulations (last codified in 1986) define ``waters of the 
United States'' as traditional navigable waters, interstate waters, all 
other waters that could affect interstate or foreign commerce, 
impoundments of waters of the United States, tributaries, the 
territorial seas, and adjacent wetlands. 33 CFR 328.3; 40 CFR 122.2.\4\
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    \2\ While section 311 uses the phrase ``navigable waters of the 
United States,'' EPA has interpreted it to have the same breadth as 
the phrase ``navigable waters'' used elsewhere in section 311, and 
in other sections of the CWA. See United States v. Texas Pipe Line 
Co., 611 F.2d 345, 347 (10th Cir. 1979); United States v. Ashland 
Oil & Transp. Co., 504 F.2d 1317, 1324-25 (6th Cir. 1974). In 2002, 
EPA revised its regulatory definition of ``waters of the United 
States'' in 40 CFR part 112 to ensure that the language of the rule 
was consistent with the regulatory language of other CWA programs. 
Oil Pollution Prevention & Response; Non-Transportation-Related 
Onshore & Offshore Facilities, 67 FR 47042, July 17, 2002. A 
district court vacated the rule for failure to comply with the 
Administrative Procedure Act, and reinstated the prior regulatory 
language. American Petroleum Ins. v. Johnson, 541 F. Supp. 2d 165 
(D. D.C. 2008). However, EPA interprets ``navigable waters of the 
United States'' in CWA section 311(b), in the pre-2002 regulations, 
and in the 2002 rule to have the same meaning as ``navigable 
waters'' in CWA section 502(7).
    \3\ For example, the CWA section 402 (33 U.S.C. 1342) program 
regulates discharges of pollutants from ``point sources'' to 
``waters of the United States,'' whether these pollutants reach 
jurisdictional waters directly or indirectly. The plurality opinion 
in Rapanos noted that ``there is no reason to suppose that our 
construction today significantly affects the enforcement of Sec.  
1342. . . . The Act does not forbid the `addition of any pollutant 
directly to navigable waters from any point source,' but rather the 
`addition of any pollutant to navigable waters.' '' 547 U.S. at 743.
    \4\ There are numerous regulations that utilize the definition 
of ``waters of the United States'' and each is codified consistent 
with its place in a particular section of the Code of Federal 
Regulations. For simplicity, throughout the preamble the agencies 
refer to the rule as organized into (a), (b), (c) provisions and 
intend the reference to encompass the appropriate cites in each 
section of the Code of Federal Regulations. For example, a reference 
to (a)(1) is a reference to all instances in the CFR identified as 
subject to this rule that state ``All waters which are currently 
used, were used in the past, or may be susceptible to use in 
interstate or foreign commerce, including all waters which are 
subject to the ebb and flow of the tide.''
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    However, the Supreme Court has issued three decisions that provide 
critical context and guidance in determining the appropriate scope of 
``waters of the United States'' covered by the CWA. In United States v. 
Riverside Bayview Homes, 474 U.S. 121 (1985) (Riverside), the Court, in 
a unanimous opinion, deferred to the Corps' ecological judgment that 
adjacent wetlands are ``inseparably bound up'' with the waters to which 
they are adjacent, and upheld the inclusion of adjacent wetlands in the 
regulatory definition of ``waters of the United States.'' Id. at 134. 
The Court observed that the broad objective of the CWA to restore and 
maintain 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.' In keeping with these views, Congress chose 
to define the waters covered by the Act broadly.'' Id. at 132-33 
(citing Senate Report No. 92-414, p. 77 (1972)).
    In Solid Waste Agency of Northern Cook County v. U.S. Army Corps of 
Engineers, 531 U.S. 159 (2001) (SWANCC), the Supreme Court 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 CWA. Although the SWANCC decision did 
not call into question earlier decisions upholding the CWA's coverage 
of wetlands or other waters ``adjacent'' to traditional navigable 
waters, it created uncertainty with regard to the jurisdiction of other 
waters and wetlands that, in many instances, may play an important role 
in protecting the integrity of the nation's waters. The majority 
opinion in SWANCC introduced the concept that it was a ``significant 
nexus'' that informed the Court's reading of CWA jurisdiction over 
waters that are not navigable in fact.
    Five years later, in Rapanos v. United States, 547 U.S. 715 (2006) 
(Rapanos), 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. In addition, Justice Kennedy's opinion indicated 
that the critical factor in determining the CWA's coverage is whether a 
water has a ``significant nexus'' to downstream traditional navigable 
waters such that the water is important to protecting the chemical, 
physical, or biological integrity of the navigable water, referring 
back to the Court's decision in SWANCC. Justice Kennedy's concurrence 
in Rapanos stated that to constitute a ``water of the United States'' 
covered by the CWA, ``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 (Kennedy, J., concurring in the 
judgment) (citing SWANCC, 531 U.S. at 167, 172). Justice Kennedy 
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.''' 547 U.S. at 780.
    In this rule, the agencies interpret the scope of the ``waters of 
the United States'' for the CWA using the goals, objectives, and 
policies of the statute, the Supreme Court case law, the relevant and 
available science, and the agencies' technical expertise and experience 
as support. In particular, the agencies looked to the objective of the 
CWA ``to restore and maintain the chemical, physical, and biological 
integrity of the Nation's waters,'' and the scientific consensus on the 
strength of the effects of upstream tributaries and adjacent waters, 
including wetlands, on downstream traditional navigable waters, 
interstate waters, and the territorial seas. An important element of 
the agencies' interpretation of the CWA is the significant nexus 
standard. This significant nexus standard was first informed by the 
ecological and hydrological connections the Supreme Court noted in 
Riverside Bayview, developed and established by the Supreme Court in 
SWANCC, and further refined in Justice Kennedy's opinion in Rapanos. 
The agencies also utilized the plurality standard in Rapanos by 
establishing boundaries on the scope of ``waters of the United States'' 
and in support of the exclusions from the definition of ``waters of the 
United States.'' The analysis used by the agencies has been supported 
by all nine of the United States Courts of Appeals that have considered 
the issue.
    The agencies assess the significance of the nexus in terms of the 
CWA's objective to ``restore and maintain the chemical, physical, and 
biological integrity of the Nation's waters.'' When the effects are 
speculative or insubstantial, the ``significant nexus'' would not be 
present. The science demonstrates that the protection of upstream 
waters is critical to maintaining the integrity of the downstream 
waters. The upstream waters identified in the rule as jurisdictional 
function as integral parts of the aquatic environment, and if these 
waters are polluted or destroyed, there is a significant effect 
downstream.
    In response to the Supreme Court opinions, the agencies issued 
guidance in 2003 (post-SWANCC) and 2008 (post-Rapanos). However, these 
two guidance documents did not provide the public or agency staff with 
the kind of information needed to ensure timely, consistent, and 
predictable jurisdictional determinations. Many waters are currently 
subject to case-specific jurisdictional analysis to determine whether a 
``significant nexus'' exists, and this time and resource intensive 
process can result in inconsistent interpretation of CWA jurisdiction 
and perpetuate ambiguity over where the CWA applies. As a result of the 
ambiguity that exists under current regulations and practice following 
these recent decisions, almost all waters and wetlands across the 
country theoretically could be subject to a case-specific 
jurisdictional determination.
    Members of Congress, developers, farmers, state and local 
governments, energy companies, and many others requested new 
regulations to make the process of identifying waters protected under 
the CWA clearer, simpler, and faster. Chief Justice Roberts' 
concurrence in Rapanos underscores

[[Page 37057]]

the importance of this rulemaking effort.\5\ In this final rule, the 
agencies are responding to those requests from across the country to 
make the process of identifying waters protected under the CWA easier 
to understand, more predictable, and more consistent with the law and 
peer-reviewed science.
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    \5\ Chief Justice Roberts' concurrence in Rapanos emphasized 
that ``[a]gencies delegated rulemaking authority under a statute 
such as the Clean Water Act are afforded generous leeway by the 
courts in interpreting the statute they are entrusted to 
administer.'' Id. at 758. Chief Justice Roberts made clear that, if 
the agencies had undertaken such a rulemaking, ``the Corps and the 
EPA would have enjoyed plenty of room to operate in developing some 
notion of an outer bound to the reach of their authority.'' Id. 
(Emphasis in original.)
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    The agencies proposed a rule clarifying the scope of waters of the 
United States April 21, 2014 (79 FR 22188), and solicited comments for 
over 200 days. This final rule reflects the over 1 million public 
comments on the proposal, the substantial majority of which supported 
the proposed rule, as well as input provided through the agencies' 
extensive public outreach effort, which included over 400 meetings 
nationwide with states, small businesses, farmers, academics, miners, 
energy companies, counties, municipalities, environmental 
organizations, other federal agencies, and many others. The agencies 
sought comment on a number of approaches to specific jurisdictional 
questions, and many of these commenters and stakeholders urged EPA to 
improve upon the April 2014 proposal, by providing more bright line 
boundaries and simplifying definitions that identify waters that are 
protected under the CWA, all for the purpose of minimizing delays and 
costs, making protection of clean water more effective, and improving 
predictability and consistency for landowners and regulated entities.
    The agencies' interpretation of the CWA's scope in this final rule 
is guided by the best available peer-reviewed science--particularly as 
that science informs the determinations as to which waters have a 
``significant nexus'' with traditional navigable waters, interstate 
waters, or the territorial seas.
    The relevant science on the relationship and downstream effects of 
waters has advanced considerably in recent years. A comprehensive 
report prepared by the EPA's Office of Research and Development 
entitled ``Connectivity of Streams and Wetlands to Downstream Waters: A 
Review and Synthesis of the Scientific Evidence'' \6\ (hereafter the 
Science Report) synthesizes the peer-reviewed science.
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    \6\ 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, 
(Washington, DC: U.S. Environmental Protection Agency, (2015)). 
http://www.epa.gov/ncea.
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    The Science Report provides much of the technical basis for this 
rule. The Science Report is based on a review of more than 1,200 peer-
reviewed publications. EPA's Science Advisory Board (SAB) conducted a 
comprehensive technical review of the Science Report and reviewed the 
adequacy of the scientific and technical basis of the proposed rule. 
The Science Report and the SAB review confirmed that:
     Waters are connected in myriad ways, including physical 
connections and the hydrologic cycle; however, connections occur on a 
continuum or gradient from highly connected to highly isolated.
     These variations in the degree of connectivity are a 
critical consideration to the ecological integrity and sustainability 
of downstream waters.
     The critical contribution of upstream waters to the 
chemical, physical, and biological integrity of downstream waters 
results from the accumulative contribution of similar waters in the 
same watershed and in the context of their functions considered over 
time.

The Science Report and the SAB review also confirmed that:
     Tributary streams, including perennial, intermittent, and 
ephemeral streams, are chemically, physically, and biologically 
connected to downstream waters, and influence the integrity of 
downstream waters.
     Wetlands and open waters in floodplains and riparian areas 
are chemically, physically, and biologically connected with downstream 
waters and influence the ecological integrity of such waters.
     Non-floodplain wetlands and open waters provide many 
functions that benefit downstream water quality and ecological 
integrity, but their effects on downstream waters are difficult to 
assess based solely on the available science.
    Although these conclusions play a critical role in informing the 
agencies' interpretation of the CWA's scope, the agencies' interpretive 
task in this rule--determining which waters have a ``significant 
nexus''--requires scientific and policy judgment, as well as legal 
interpretation. The science demonstrates that waters fall along a 
gradient of chemical, physical, and biological connection to 
traditional navigable waters, and it is the agencies' task to determine 
where along that gradient to draw lines of jurisdiction under the CWA. 
In making this determination, the agencies must rely, not only on the 
science, but also on their technical expertise and practical experience 
in implementing the CWA during a period of over 40 years. In addition, 
the agencies are guided, in part, by the compelling need for clearer, 
more consistent, and easily implementable standards to govern 
administration of the Act, including brighter line boundaries where 
feasible and appropriate.

Major Rule Provisions

    In this final rule, the agencies define ``waters of the United 
States'' to include eight categories of jurisdictional waters. The rule 
maintains existing exclusions for certain categories of waters, and 
adds additional categorical exclusions that are regularly applied in 
practice. The rule reflects the agencies' goal of providing simpler, 
clearer, and more consistent approaches for identifying the geographic 
scope of the CWA. The rule recognizes jurisdiction for three basic 
categories: Waters that are jurisdictional in all instances, waters 
that are excluded from jurisdiction, and a narrow category of waters 
subject to case-specific analysis to determine whether they are 
jurisdictional.
    Decisions about waters in each of these categories are based on the 
law, peer-reviewed science, and the agencies' technical expertise, and 
were informed by public comments. This rule replaces existing 
procedures that often depend on individual, time-consuming, and 
inconsistent analyses of the relationship between a particular stream, 
wetland, lake, or other water with downstream waters. The agencies have 
greatly reduced the extent of waters subject to this individual review 
by carefully incorporating the scientific literature and by utilizing 
agency expertise and experience to characterize the nature and strength 
of the chemical, physical, and biological connections between upstream 
and downstream waters. The result of applying this scientific analysis 
is that the agencies can more effectively focus the rule on identifying 
waters that are clearly covered by the CWA and those that are clearly 
not covered, making the rule easier to understand, consistent, and 
environmentally more protective.
    The jurisdictional categories reflect the current state of the best 
available science, and are based upon the law and Supreme Court 
decisions. The agencies will continue a transparent review of the 
science, and learn from on-going

[[Page 37058]]

experience and expertise as the agencies implement the rule. If 
evolving science and the agencies' experience lead to a need for action 
to alter the jurisdictional categories, any such action will be 
conducted as part of a rule-making process.
    The first three types of jurisdictional waters, traditional 
navigable waters, interstate waters, and the territorial seas, are 
jurisdictional by rule in all cases. The fourth type of water, 
impoundments of jurisdictional waters, is also jurisdictional by rule 
in all cases. The next two types of waters, ``tributaries'' and 
``adjacent'' waters, are jurisdictional by rule, as defined, because 
the science confirms that they have a significant nexus to traditional 
navigable waters, interstate waters, or territorial seas. For waters 
that are jurisdictional by rule, no additional analysis is required.
    The final two types of jurisdictional waters are those waters found 
after a case-specific analysis to have a significant nexus to 
traditional navigable waters, interstate waters, or the territorial 
seas, either alone or in combination with similarly situated waters in 
the region. Justice Kennedy acknowledged the agencies could establish 
more specific regulations or establish a significant nexus on a case-
by-case basis, Rapanos at 782, and for these waters the agencies will 
continue to assess significant nexus on a case-specific basis.
    The major elements of the final rule are briefly summarized here.

Traditional Navigable Waters, Interstate Waters, Territorial Seas, and 
Impoundments of Jurisdictional Waters

    Consistent with existing regulations and the April 2014 proposed 
rule, the final rule includes traditional navigable waters, interstate 
waters, territorial seas, and impoundments of jurisdictional waters in 
the definition of ``waters of the United States.'' These waters are 
jurisdictional by rule.

Tributaries

    Previous definitions of ``waters of the United States'' regulated 
all tributaries without qualification. This final rule more precisely 
defines ``tributaries'' as waters that are characterized by the 
presence of physical indicators of flow--bed and banks and ordinary 
high water mark--and that contribute flow directly or indirectly to a 
traditional navigable water, an interstate water, or the territorial 
seas. The rule concludes that such tributaries are ``waters of the 
United States.'' The great majority of tributaries as defined by the 
rule are headwater streams that play an important role in the transport 
of water, sediments, organic matter, nutrients, and organisms to 
downstream waters. The physical indicators of bed and banks and 
ordinary high water mark demonstrate that there is sufficient volume, 
frequency, and flow in such tributaries to a traditional navigable 
water, interstate water, or the territorial seas to establish a 
significant nexus. ``Tributaries,'' as defined, are jurisdictional by 
rule.
    The rule only covers as tributaries those waters that science tells 
us provide chemical, physical, or biological functions to downstream 
waters and that meet the significant nexus standard. The agencies 
identify these functions in the definition of ``significant nexus'' at 
paragraph (c)(5). Features not meeting this legal and scientific test 
are not jurisdictional under this rule. The rule continues the current 
policy of regulating ditches that are constructed in tributaries or are 
relocated tributaries or, in certain circumstances drain wetlands, or 
that science clearly demonstrates are functioning as a tributary. These 
jurisdictional waters affect the chemical, physical, and biological 
integrity of downstream waters. The rule further reduces existing 
confusion and inconsistency regarding the regulation of ditches by 
explicitly excluding certain categories of ditches, such as ditches 
that flow only after precipitation. Further, the rule explicitly 
excludes from the definition of ``waters of the United States'' 
erosional features, including gullies, rills, and ephemeral features 
such as ephemeral streams that do not have a bed and banks and ordinary 
high water mark.

Adjacent Waters

    The agencies determined that ``adjacent waters,'' as defined in the 
rule, have a significant nexus to traditional navigable waters, 
interstate waters, and the territorial seas based upon their 
hydrological and ecological connections to, and interactions with, 
those waters. Under this final rule, ``adjacent'' means bordering, 
contiguous, or neighboring, including waters separated from other 
``waters of the United States'' by constructed dikes or barriers, 
natural river berms, beach dunes and the like. Further, waters that 
connect segments of, or are at the head of, a stream or river are 
``adjacent'' to that stream or river. ``Adjacent waters'' include 
wetlands, ponds, lakes, oxbows, impoundments, and similar water 
features. However, it is important to note that ``adjacent waters'' do 
not include waters that are subject to established normal farming, 
silviculture, and ranching activities as those terms are used in 
Section 404(f) of the CWA.
    The final rule establishes a definition of ``neighboring'' for 
purposes of determining adjacency. In the rule, the agencies identify 
three circumstances under which waters would be ``neighboring'' and 
therefore ``waters of the United States'':
    (1) Waters located in whole or in part within 100 feet of the 
ordinary high water mark of a traditional navigable water, interstate 
water, the territorial seas, an impoundment of a jurisdictional water, 
or a tributary, as defined in the rule.
    (2) Waters located in whole or in part in the 100-year floodplain 
and that are within 1,500 feet of the ordinary high water mark of a 
traditional navigable water, interstate water, the territorial seas, an 
impoundment, or a tributary, as defined in the rule (``floodplain 
waters'').
    (3) Waters located in whole or in part within 1,500 feet of the 
high tide line of a traditional navigable water or the territorial seas 
and waters located within 1,500 feet of the ordinary high water mark of 
the Great Lakes.
    The agencies emphasize that the rule has defined as ``adjacent 
waters'' those waters that currently available science demonstrates 
possess the requisite connection to downstream waters and function as a 
system to protect the chemical, physical, or biological integrity of 
those waters. The agencies also emphasize that the rule does not cover 
``adjacent waters'' that are otherwise excluded. Further, the agencies 
recognize the establishment of bright line boundaries in the rule for 
adjacency does not in any way restrict states from considering state 
specific information and concerns, as well as emerging science to 
evaluate the need to more broadly protect their waters under state law. 
The CWA establishes both national and state roles to ensure that states 
specific circumstances are properly considered to complement and 
reinforce actions taken at the national level.
    ``Adjacent'' waters as defined are jurisdictional by rule. The 
agencies recognize that there are individual waters outside of the 
``neighboring'' boundaries stated above where the science may 
demonstrate through a case-specific analysis that there exists a 
significant nexus to a downstream traditional navigable water, 
interstate water, or the territorial seas. However, these waters are 
not determined jurisdictional by rule and will be evaluated through a 
case-specific analysis. The strength of the science and

[[Page 37059]]

the significance of the nexus will be established on a case-specific 
basis as described below.

Case-Specific Significant Nexus

    The rule identifies particular waters that are not jurisdictional 
by rule but are subject to case-specific analysis to determine if a 
significant nexus exists and the water is a ``water of the United 
States.'' This category of case-specific waters is based upon available 
science and the law, and in response to public comments that encouraged 
the agencies to ensure more consistent determinations and reduce the 
complexity of conducting jurisdictional determinations. Consistent with 
the significant nexus standard articulated in the Supreme Court 
opinions, waters are ``waters of the United States'' if they 
significantly affect the chemical, physical, or biological integrity of 
traditional navigable waters, interstate waters, or the territorial 
seas. This determination will most typically be made on a water 
individually, but can, when warranted, be made in combination with 
other waters where waters function together.
    In this final rule, the agencies have identified by rule, five 
specific types of waters in specific regions that science demonstrates 
should be subject to a significant nexus analysis and are considered 
similarly situated by rule because they function alike and are 
sufficiently close to function together in affecting downstream waters. 
These five types of waters are Prairie potholes, Carolina and Delmarva 
bays, pocosins, western vernal pools in California, and Texas coastal 
prairie wetlands. Consistent with Justice Kennedy's opinion in Rapanos, 
the agencies determined that such waters should be analyzed ``in 
combination'' (as a group, rather than individually) in the watershed 
that drains to the nearest traditional navigable water, interstate 
water, or the territorial seas when making a case-specific analysis of 
whether these waters have a significant nexus to traditional navigable 
waters, interstate waters, or territorial seas.
    The final rule also provides that waters within the 100-year 
floodplain of a traditional navigable water, interstate water, or the 
territorial seas and waters within 4,000 feet of the high tide line or 
the ordinary high water mark of a traditional navigable water, 
interstate water, the territorial seas, impoundments, or covered 
tributary are subject to case-specific significant nexus 
determinations, unless the water is excluded under paragraph (b) of the 
rule. The science available today does not establish that waters beyond 
those defined as ``adjacent'' should be jurisdictional as a category 
under the CWA, but the agencies' experience and expertise indicate that 
there are many waters within the 100-year floodplain of a traditional 
navigable water, interstate water, or the territorial seas or out to 
4,000 feet where the science demonstrates that they have a significant 
effect on downstream waters.
    In circumstances where waters within the 100-year floodplain of a 
traditional navigable water, interstate water, or the territorial seas 
or within 4,000 feet of the high tide line or ordinary high water mark 
are subject to a case-specific significant nexus analysis and such 
waters may be evaluated as ``similarly situated,'' it must be first 
demonstrated that these waters function alike and are sufficiently 
close to function together in affecting downstream waters. The 
significant nexus analysis must then be conducted based on 
consideration of the functions provided by those waters in combination 
in the point of entry watershed. A ``similarly situated'' analysis is 
conducted where it is determined that there is a likelihood that there 
are waters that function together to affect downstream water integrity. 
To provide greater clarity and transparency in determining what 
functions will be considered in determining what constitutes a 
significant nexus, the final rule lists specific functions that the 
agencies will consider.
    In establishing both the 100-year floodplain and the 4,000 foot 
bright line boundaries for these case-specific significant nexus 
determinations in the rule, the agencies are carefully applying the 
available science. Consistent with the CWA, the agencies will work with 
the states in connection with the prevention, reduction and elimination 
of pollution from state waters. The agencies will work with states to 
more closely evaluate state-specific circumstances that may be present 
within their borders and, as appropriate, encourage states to develop 
rules that reflect their circumstances and emerging science to ensure 
consistent and effective protection for waters in the states. As is the 
case today, nothing in this rule restricts the ability of states to 
more broadly protect state waters.

Exclusions

    All existing exclusions from the definition of ``waters of the 
United States'' are retained, and several exclusions reflecting 
longstanding agency practice are added to the regulation for the first 
time.
    Prior converted cropland and waste treatment systems have been 
excluded from the definition of ``waters of the United States'' 
definition since 1992 and 1979 respectively, and continue to be 
excluded. Ministerial changes are made for purposes of clarity, but 
these two exclusions remain substantively and operationally unchanged. 
The agencies add exclusions for waters and features previously 
identified as generally exempt (e.g., exclusion for certain ditches 
that are not located in or drain wetlands) in preamble language from 
Federal Register documents by the Corps on November 13, 1986, and by 
EPA on June 6, 1988. This is the first time these exclusions have been 
established by rule. The agencies for the first time also establish by 
rule that certain ditches are excluded from jurisdiction, including 
ditches with ephemeral flow that are not a relocated tributary or 
excavated in a tributary, and ditches with intermittent flow that are 
not a relocated tributary, or excavated in a tributary, or drain 
wetlands. The agencies add exclusions for groundwater and erosional 
features, as well as exclusions for some waters that were identified in 
public comments as possibly being found jurisdictional under proposed 
rule language where this was never the agencies' intent, such as 
stormwater control features constructed to convey, treat, or store 
stormwater, and cooling ponds that are created in dry land. These 
exclusions reflect the agencies' current practice, and their inclusion 
in the rule as specifically excluded furthers the agencies' goal of 
providing greater clarity over what waters are and are not protected 
under the CWA.

Role of States and Tribes Under the Clean Water Act

    States and tribes play a vital role in the implementation and 
enforcement of the CWA. Section 101(b) of the CWA states 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 CWA.
    Of particular importance, states and tribes may be authorized by 
the EPA to administer the permitting programs of CWA sections 402 and 
404. Forty-six states and the U.S. Virgin Islands are authorized to 
administer the NPDES program under section 402, while two states 
administer the section 404 program. The CWA identifies the waters over 
which states may assume section 404 permitting jurisdiction. See CWA 
section 404(g)(1). The scope of waters

[[Page 37060]]

that are subject to state and tribal permitting is a separate inquiry 
and must be based on the statutory language in CWA section 404. States 
administer approved CWA section 404 programs for ``waters of the United 
States'' within the state, except those waters remaining under Corps 
jurisdiction pursuant to CWA section 404(g)(1) as identified in a 
Memorandum of Agreement between the state and the Corps. 40 CFR 233.14; 
40 CFR 233.70(c)(2); 40 CFR 233.71(d)(2). EPA has initiated a separate 
process to address how the EPA can best clarify assumable waters for 
dredged and fill material permit programs pursuant to the Clean Water 
Act section 404(g)(1). 80 FR 13539 (Mar. 16, 2015). Additional CWA 
programs that utilize the definition of ``waters of the United States'' 
and are of importance to the states and tribes include the section 311 
oil spill prevention and response program, the water quality standards 
and total maximum daily load (TMDL) programs under section 303, and the 
section 401 state water quality certification process.
    States and federally-recognized tribes, consistent with the CWA, 
retain full authority to implement their own programs to more broadly 
and more fully protect the waters in their jurisdiction. Under section 
510 of the CWA, unless expressly stated, nothing in the CWA precludes 
or denies the right of any state to establish more protective standards 
or limits than the Federal CWA. Congress has also provided roles for 
eligible Indian tribes to administer CWA programs over their 
reservations and expressed a preference for tribal regulation of 
surface water quality on Indian reservations to ensure compliance with 
the goals of the CWA. See 33 U.S.C. 1377; 56 FR 64876, 64878-79 (Dec. 
12, 1991)). Tribes also have inherent sovereign authority to establish 
more protective standards or limits than the Federal CWA. Where 
appropriate, references to states in this document may also include 
eligible tribes. Many states and tribes, for example, regulate 
groundwater, and some others protect wetlands that are vital to their 
environment and economy but outside the jurisdiction of the CWA. 
Nothing in this rule limits or impedes any existing or future state or 
tribal efforts to further protect their waters. In fact, providing 
greater clarity regarding what waters are subject to CWA jurisdiction 
will reduce the need for permitting authorities, including the states 
and tribes with authorized section 402 and 404 CWA permitting programs, 
to make jurisdictional determinations on a case-specific basis.

Overview of the Preamble

    The remainder of this preamble is organized as follows. Section III 
(Significant Nexus Standard) provides additional background on the 
rule, including a discussion of Supreme Court precedent, the science 
underpinning the rule, and the agencies' overall interpretive approach 
to applying the significant nexus standard. Section IV (Definition of 
Waters of the United States) explains the provisions of the final rule, 
including subsections on each of the major elements of the rule. 
Section V summarizes the economic analysis of the rule and Section VI 
addresses Related Acts of Congress, Executive Orders and Agency 
Initiatives.

III. Significant Nexus Standard

    With this rule, the agencies interpret the scope of the ``waters of 
the United States'' for the CWA in light of the goals, objectives, and 
policies of the statute, the Supreme Court case law, the relevant and 
available science, and the agencies' technical expertise and 
experience. The key to the agencies' interpretation of the CWA is the 
significant nexus standard, as established and refined in Supreme Court 
opinions: Waters are ``waters of the United States'' if they, 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 agencies interpret specific aspects of the significant nexus 
standard in light of the science, the law, and the agencies' technical 
expertise: The scope of the region in which to evaluate waters when 
making a significant nexus determination; the waters to evaluate in 
combination with each other; and the functions provided by waters and 
strength of those functions, and when such waters significantly affect 
the chemical, physical, or biological integrity of the downstream 
traditional navigable waters, interstate waters, or the territorial 
seas.
    In the rule, the agencies determine that tributaries, as defined 
(``covered tributaries''), and ``adjacent waters'', as defined 
(``covered adjacent waters''), have a significant nexus to downstream 
traditional navigable waters, interstate waters, and the territorial 
seas and therefore are ``waters of the United States.'' In the rule, 
the agencies also establish that defined sets of additional waters may 
be determined to have a significant nexus on a case-specific basis: (1) 
Five specific types of waters that the agencies conclude are 
``similarly situated'' and therefore must be analyzed ``in 
combination'' in the watershed that drains to the nearest traditional 
navigable water, interstate water, or the territorial seas when making 
a case-specific significant nexus analysis; and (2) waters within the 
100-year floodplain of a traditional navigable water, interstate water, 
or the territorial seas, or waters within 4,000 feet of the high tide 
line or ordinary high water mark of traditional navigable waters, 
interstate waters, the territorial seas, impoundments or covered 
tributaries. The rule establishes a definition of significant nexus, 
based on Supreme Court opinions and the science, to use when making 
these case-specific determinations.
    Significant nexus is not a purely scientific determination. The 
opinions of the Supreme Court have noted that as the agencies charged 
with interpreting the statute, EPA and the Corps must develop the outer 
bounds of the scope of the CWA, while science does not provide bright 
line boundaries with respect to where ``water ends'' for purposes of 
the CWA. Therefore, the agencies' interpretation of the CWA is informed 
by the Science Report and the review and comments of the SAB, but not 
dictated by them. With this context, this section addresses, first, the 
Supreme Court case law and the significant nexus standard, second, the 
relevant scientific conclusions reached by analysis of existing 
scientific literature, and third, the agencies' significant nexus 
determinations underpinning the rule. Section IV of the preamble 
addresses in more detail the precise definitions of the covered waters 
promulgated by the agencies to provide the bright line boundaries 
identifying ``waters of the United States.''

A. The Significant Nexus Standard

    Congress enacted the CWA ``to restore and maintain the chemical, 
physical, and biological integrity of the Nation's waters.'' Section 
101(a). The agencies' longstanding regulations define ``waters of the 
United States'' for purposes of the Clean Water Act, and the Supreme 
Court has addressed the scope of ``waters of the United States'' 
protected by the CWA in three cases. The significant nexus standard 
evolved through those cases.
    In United States v. Riverside Bayview Homes, 474 U.S. 121 (1985) 
(Riverside), which involved wetlands adjacent to a traditional 
navigable water in Michigan, the Court, in a unanimous opinion, 
deferred to the Corps' ecological judgment that adjacent wetlands are 
``inseparably bound up'' with the waters

[[Page 37061]]

to which they are adjacent, and upheld the inclusion of adjacent 
wetlands in the regulatory definition of ``waters of the United 
States.'' Id. at 134. The Court observed that the broad objective of 
the CWA to restore and maintain 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.' In keeping 
with these views, Congress chose to define the waters covered by the 
Act broadly.'' Id. at 132-33 (citing Senate Report No. 92-414). 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. 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 issue of CWA jurisdiction over ``waters of the United States'' 
was addressed again by the Supreme Court 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 
regulatory authority under the CWA. The SWANCC Court noted that in 
Riverside 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 our reading of the CWA'' in that 
case. Id. at 167. SWANCC did not invalidate any parts of the regulatory 
definition of ``waters of the United States.''
    Five years after SWANCC, the Court again addressed the 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 CWA 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. 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 concurred that the cases should be remanded for 
further decision making, and stated 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). Justice Kennedy concluded that ``The required nexus must be 
assessed in terms of the statute's goals and purposes. Congress enacted 
the law to `restore and maintain the chemical, physical, and biological 
integrity of the Nation's waters,' 33 U.S.C. 1251(a), and it pursued 
that objective by restricting dumping and filling in `navigable 
waters,' Sec. Sec.  1311(a), 1362(12).'' Id. at 779. 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.' '' 547 U.S. at 780. Justice Kennedy's opinion notes that 
such a relationship with navigable waters must be more than 
``speculative or insubstantial.'' Id. at 780.
    While Justice Kennedy's opinion focused on adjacent wetlands in 
light of the facts of the cases before him, his opinion is clear that a 
significant nexus is the basis for jurisdiction to protect non-
navigable waters and wetlands under the CWA (id. at 759), and there is 
no indication in his opinion that the analytical framework his opinion 
provides for determining significant nexus for adjacent wetlands is 
limited to adjacent wetlands. In addition, the four dissenting Justices 
in Rapanos, who would have affirmed the court of appeals' application 
of the agencies' regulation, 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). Neither the 
plurality nor the Kennedy opinion invalidated any of the current 
regulatory provisions defining ``waters of the United States.''
    Chief Justice Roberts' concurrence in Rapanos emphasized that 
``[a]gencies delegated rulemaking authority under a statute such as the 
Clean Water Act are afforded generous leeway by the courts in 
interpreting the statute they are entrusted to administer.'' Id. at 
758. Chief Justice Roberts made clear that, if the agencies had 
undertaken such a rulemaking, ``the Corps and the EPA would have 
enjoyed plenty of room to operate in developing some notion of an outer 
bound to the reach of their authority.'' Id. (Emphasis in original.)
    The agencies utilize the significant nexus standard, as articulated 
by Justice Kennedy's opinion and informed by the unanimous opinion in 
Riverside Bayview and the plurality opinion in Rapanos which all 
recognize that the Act and the agencies must identify the scope of CWA 
jurisdiction ``on this continuum to find the limit of `waters,' '' 
Riverside Bayview at 132, to interpret the scope of the statutory term 
``waters of the United States.'' While a significant nexus 
determination is primarily weighted in the scientific evidence and 
criteria, the agencies also consider the statutory language, the 
statute's goals, objectives and policies, the case law, and the 
agencies' technical expertise and experience when interpreting the 
terms of the CWA.

B. Science Report

    EPA's Office of Research and Development prepared the Science 
Report, a peer-reviewed compilation and analysis of published peer-
reviewed scientific literature summarizing the current scientific 
understanding of the

[[Page 37062]]

connectivity of and mechanisms by which streams and wetlands, singly or 
in combination, affect the chemical, physical, and biological integrity 
of downstream waters. The final Science Report is available in the 
docket and at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=296414.
    The process for developing the Science Report followed standard 
information quality guidelines for EPA. In September 2013, EPA released 
a draft of the Science Report for an independent SAB review and invited 
submissions of public comments for consideration by the SAB panel. In 
October 2014, after several public meetings and hearings, the SAB 
completed its peer review of the draft Science Report. The SAB was 
highly supportive of the draft Science Report's conclusions regarding 
streams, riparian and floodplain wetlands, and open waters, and 
recommended strengthening the conclusion regarding non-floodplain 
waters to include a more definitive statement that reflects how 
numerous functions of such waters sustain the integrity of downstream 
waters.\7\ The final peer review report is available on the SAB Web 
site, as well as in the docket for this rulemaking. EPA revised the 
draft Science Report based on comments from the public and 
recommendations from the SAB panel.
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    \7\ U.S. EPA. 2014. SAB review of the draft EPA report 
Connectivity of Streams and Wetlands to Downstream Waters: A Review 
and Synthesis of the Scientific Evidence. EPA-SAB-15-001, U.S. 
Environmental Protection Agency, Washington, DC. (``SAB 2014a.'')
---------------------------------------------------------------------------

    The SAB was established in 1978 by the Environmental Research, 
Development, and Demonstration Authorization Act (ERDDAA), to provide 
independent scientific and technical advice to the EPA Administrator on 
the technical basis for Agency positions and regulations. Advisory 
functions include peer review of EPA's technical documents, such as the 
Science Report. At the time the peer review was completed, the 
chartered SAB was comprised of more than 50 members from a variety of 
sectors including academia, non-profit organizations, foundations, 
state governments, consulting firms, and industry. To conduct the peer 
review, EPA's SAB staff formed an ad hoc panel based on nominations 
from the public to serve as the primary reviewers. The panel consisted 
of 27 technical experts in an array of relevant fields, including 
hydrology, wetland and stream ecology, biology, geomorphology, 
biogeochemistry, and freshwater science. Similar to the chartered SAB, 
the panel members represented sectors including academia, a federal 
government agency, non-profit organizations, and consulting firms. The 
chair of the panel was a member of the chartered SAB.
    The SAB process is open and transparent, consistent with the 
Federal Advisory Committee Act, 5 U.S.C., App 2, and agency policies 
regarding Federal advisory committees. Consequently, the SAB has an 
approved charter, which must be renewed biennially, announces its 
meetings in the Federal Register, and provides opportunities for public 
comment on issues before the Board. The SAB staff announced via the 
Federal Register that they sought public nominations of technical 
experts to serve on the expert panel: SAB Panel for the Review of the 
EPA Water Body Connectivity Report (via a similar process the public 
also is invited to nominate chartered SAB members). 78 FR 15012 (Mar. 
8, 2013). The SAB staff then invited the public to comment on the list 
of candidates for the panel. Once the panel was selected, the SAB staff 
posted a memo on its Web site addressing the formation of the panel and 
the set of determinations that were necessary for its formation (e.g., 
no conflicts of interest). In the public notice of the first public 
meetings interested members of the public were invited to submit 
relevant comments for the SAB Panel to consider pertaining to the 
review materials, including the charge to the Panel. Over 133,000 
public comments were received by the Docket. Every meeting was open to 
the public, noticed in the Federal Register, and had time allotted for 
the public to present their views. In total, the Panel held a two-day 
in-person meeting in Washington, DC, in December 2013, and three four-
hour public teleconferences in April, May, and June 2014. The SAB Panel 
also compiled four draft versions of its peer review report to inform 
and assist the meeting deliberations that were posted on the SAB Web 
site. In September 2014, the chartered SAB conducted a public 
teleconference to conduct the quality review of the Panel's final draft 
peer review report. The peer review report was approved at that 
meeting, and revisions were made to reflect the chartered SAB's review. 
The culmination of that public process was the release of the final 
peer review report in October 2014. All meeting minutes and draft 
reports are available on the SAB Web site for public access.
    The final Science Report states that connectivity is a foundational 
concept in hydrology and freshwater ecology. 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 for purposes of interpreting the scope of ``waters of the 
United States'' under the CWA serves to demonstrate the ``nexus'' 
between upstream water bodies and the downstream traditional navigable 
water, interstate water, or the territorial sea. The scientific 
literature does not use the term ``significant'' as it is defined in a 
legal context, but it does provide information on the strength of the 
effects on the chemical, physical, and biological functioning of the 
downstream water bodies from the connections among covered tributaries, 
covered adjacent waters, and case-specific waters and those downstream 
waters. The scientific literature also does not use the terms 
traditional navigable waters, interstate waters, or the territorial 
seas. However, evidence of strong chemical, physical, and biological 
connections to larger rivers, estuaries, and lakes applies to that 
subset of rivers, estuaries, and lakes that are traditional navigable 
waters, interstate waters, or the territorial seas.
    The Science Report presents evidence of those connections from 
various categories of waters, evaluated singly or in combination, which 
affect downstream waters and the strength of that effect. The 
objectives of the Science Report are (1) to provide a context for 
considering the evidence of connections between downstream waters and 
their tributary waters, and (2) to summarize current understanding 
about these connections, the factors that influence them, and the 
mechanisms by which the connections affect the function or condition of 
downstream waters. 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 covered adjacent waters perform, such as storing and 
cleansing water; movement of organisms or their seeds and eggs; and 
hydrologic and biogeochemical interactions occurring in and among 
surface and groundwater flows, including hyporheic zones \8\ and 
alluvial aquifers.
---------------------------------------------------------------------------

    \8\ The hyporheic zone is the subsurface area immediately below 
the bed of intermittent and ephemeral streams that remains wet even 
when there is no surface flow. These areas are extremely important 
to macro-benthic organisms critical to the bio-chemical integrity of 
streams.
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    The Science Report presents five major conclusions:

[[Page 37063]]

Conclusion 1: Streams
    The scientific literature unequivocally demonstrates that streams, 
individually or cumulatively, exert a strong influence on the chemical, 
physical, and biological integrity of downstream waters. All tributary 
streams, including perennial, intermittent, and ephemeral streams, are 
chemically, physically, and biologically connected to downstream rivers 
via channels and associated alluvial deposits where water and other 
materials are concentrated, mixed, transformed, and transported. 
Streams are the dominant source of water in most rivers, and the 
majority of tributaries are perennial, intermittent, or ephemeral 
headwater streams. Headwater streams also convey water into local 
storage compartments such as ponds, shallow aquifers, and floodplains, 
and into regional and alluvial aquifers; these local storage 
compartments are important sources of water for maintaining baseflow in 
rivers. In addition to water, streams transport sediment, wood, organic 
matter, nutrients, chemical contaminants, and many of the organisms 
found in rivers. The scientific literature provides robust evidence 
that streams are biologically connected to downstream waters by the 
dispersal and migration of aquatic and semiaquatic organisms, including 
fish, amphibians, plants, microorganisms, and invertebrates, that use 
both upstream and downstream habitats during one or more stages of 
their life cycles, or provide food resources to downstream communities. 
In addition to material transport and biological connectivity, 
ephemeral, intermittent, and perennial flows influence fundamental 
biogeochemical processes by connecting channels and shallow groundwater 
with other landscape elements. Chemical, physical, and biological 
connections between streams and downstream waters interact via 
integrative processes such as nutrient spiraling. This occurs when 
stream communities assimilate and chemically transform large quantities 
of nitrogen and other nutrients that otherwise would be transported 
directly downstream, thereby increasing nutrient loads and associated 
impairments due to excess nutrients in downstream waters. Science 
Report at ES-2.
Conclusion 2: Riparian/Floodplain Wetlands and Open Waters
    The scientific literature clearly shows that wetlands and open 
waters in riparian areas and floodplains are chemically, physically, 
and biologically integrated with rivers via functions that improve 
downstream water quality, including the temporary storage and 
deposition of channel-forming sediment and woody debris, temporary 
storage of local groundwater that supports baseflow in rivers, and 
transformation and transport of stored organic matter. Riparian/
floodplain wetlands and open waters improve water quality through the 
assimilation, transformation, and sequestration of pollutants, 
including excess nutrients and chemical contaminants such as pesticides 
and metals that can degrade downstream water integrity. In addition to 
providing effective buffers to protect downstream waters from point 
source and nonpoint source pollution, these systems form integral 
components of river food webs, providing nursery habitat for breeding 
fish and amphibians, colonization opportunities for stream 
invertebrates, and maturation habitat for stream insects. Lateral 
expansion and contraction of the river in its floodplain result in an 
exchange of organic matter and organisms, including fish populations 
that are adapted to use floodplain habitats for feeding and spawning 
during high water, that are critical to river ecosystem function. 
Riparian/floodplain wetlands and open waters also affect the integrity 
of downstream waters by subsequently releasing (desynchronizing) 
floodwaters and retaining large volumes of stormwater, sediment, and 
contaminants in runoff that could otherwise negatively affect the 
condition or function of downstream waters. Science Report at ES-2 to 
ES-3.
Conclusion 3: Non-Floodplain Wetlands and Open Waters
    Wetlands and open waters in non-floodplain landscape settings 
(``non-floodplain wetlands'') provide numerous functions that benefit 
downstream water integrity. These functions include storage of 
floodwater; recharge of groundwater that sustains river baseflow; 
retention and transformation of nutrients, metals, and pesticides; 
export of organisms or seeds to downstream waters; and habitats needed 
for stream species. This diverse group of wetlands (e.g., many Prairie 
potholes or vernal pools) can be connected to downstream waters through 
surface water, shallow subsurface water, and groundwater flows, and 
through biological and chemical connections.
    In general, connectivity of non-floodplain wetlands occurs along a 
gradient, and can be described in terms of the frequency, duration, 
magnitude, timing, and rate of change of water, material, and biotic 
fluxes to downstream waters. These descriptors are influenced by 
climate, geology, and terrain, which interact with factors such as the 
magnitudes of the various functions within wetlands (e.g., amount of 
water storage or carbon export) and their proximity to downstream 
waters to determine where wetlands occur along the connectivity 
gradient. At one end of this gradient, the functions of non-floodplain 
wetlands clearly affect the condition of downstream waters if a visible 
(e.g., channelized) surface water or a regular shallow subsurface-water 
connection to the river network is present. For non-floodplain wetlands 
lacking a channelized surface or regular shallow subsurface connection 
(i.e., those at intermediate points along the gradient of 
connectivity), generalizations about their specific effects on 
downstream waters from the available literature are difficult because 
information on both function and connectivity is needed. Science Report 
at ES-3.
Conclusion 4: Degrees and Determinants of Connectivity
    Connectivity of streams and wetlands to downstream waters occurs 
along a gradient that can be described in terms of the frequency, 
duration, magnitude, timing, and rate of change of water, material, and 
biotic fluxes to downstream waters. These terms, which we refer to 
collectively as connectivity descriptors, characterize the range over 
which streams and wetlands vary and shift along the connectivity 
gradient in response to changes in natural and anthropogenic factors 
and, when considered in a watershed context, can be used to predict 
probable effects of different degrees of connectivity over time. The 
evidence unequivocally demonstrates that the stream channels and 
riparian/floodplain wetlands or open waters that together form river 
networks are clearly connected to downstream waters in ways that 
profoundly influence downstream water integrity. The connectivity and 
effects of non-floodplain wetlands and open waters are more variable 
and thus more difficult to address solely from evidence available in 
peer-reviewed studies. Science Report at ES-3 to ES-4.
Conclusion 5: Cumulative Effects
    The incremental effects of individual streams and wetlands are 
cumulative across entire watersheds, and therefore, must be evaluated 
in context with other streams and wetlands. Downstream waters are the 
time-integrated result of all waters contributing to them. For example, 
the amount of water or biomass contributed by a specific

[[Page 37064]]

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.
    When considering the effect of an individual stream or wetland, all 
contributions and functions of that stream or wetland should be 
evaluated cumulatively. For example, the same stream transports water, 
removes excess nutrients, transports pollutants, mitigates flooding, 
and provides refuge for fish when conditions downstream are 
unfavorable; if any of these functions is ignored, the overall effect 
of that stream would be underestimated. Science Report at ES-5 to ES-6.
SAB Review of the Proposed Rule
    In addition to its peer review of the draft Science Report, in a 
separate effort the SAB also reviewed the adequacy of the scientific 
and technical basis of the proposed rule and provided its advice and 
comments on the proposal in September 2014.\9\ The same SAB Panel that 
reviewed the draft Science Report met via two public teleconferences in 
August 2014 to discuss the scientific and technical basis of the 
proposed rule. The Panel submitted comments to the Chair of the 
chartered SAB. A work group of chartered SAB members considered 
comments provided by panel members, agency representatives, and the 
public on the adequacy of the science informing the rule. This work 
group then led the September 2014 public teleconference discussion of 
the chartered SAB. The public had an opportunity to submit oral or 
written comments during these two public meetings. The SAB's final 
letter to the EPA Administrator can be found on the SAB Web site and in 
the docket for this rule.
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    \9\ U.S. EPA. 2014. SAB Consideration of the Adequacy of the 
Scientific and Technical Basis of the EPA's Proposed Rule titled 
``Definition of Waters of the United States under the Clean Water 
Act.'' EPA-SAB-14-007, U.S. Environmental Protection Agency, 
Washington, DC. (``SAB 2014b.'')
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    The SAB found that the available science provides an adequate 
scientific basis for the key components of the proposed rule. The SAB 
noted that although water bodies differ in degree of connectivity that 
affects the extent of influence they exert on downstream waters (i.e., 
they exist on a ``connectivity gradient''), the available science 
supports the conclusion that the types of water bodies identified as 
``waters of the United States'' in the proposed rule exert strong 
influence on the chemical, physical, and biological integrity of 
downstream waters. In particular, the SAB expressed support for the 
proposed rule's inclusion of tributaries and ``adjacent waters'' as 
categorical waters of the United States and the inclusion of ``other 
waters'' on a case-specific basis, though noting that certain ``other 
waters'' can be determined as a subcategory to be similarly situated.
    Regarding tributaries, the SAB found, ``[t]here is strong 
scientific evidence to support the EPA's proposal to include all 
tributaries within the jurisdiction of the Clean Water Act. 
Tributaries, as a group, exert strong influence on the physical, 
chemical, and biological integrity of downstream waters, even though 
the degree of connectivity is a function of variation in the frequency, 
duration, magnitude, predictability, and consequences of physical, 
chemical, and biological processes.'' The Board advised EPA to 
reconsider the definition of tributaries because not all tributaries 
have ordinary high water marks (e.g., ephemeral streams with arid and 
semi-arid environments or in low gradient landscapes where the flow of 
water is unlikely to cause an ordinary high water mark). The SAB also 
advised EPA to consider changing the wording in the definition to 
``bed, bank, and other evidence of flow.'' SAB 2014b at 2. The agencies 
did not make this change because this recommendation seemed to suggest 
that any hydrologic connection is sufficient for CWA jurisdiction. The 
definition of ``tributary'' in the rule better identifies tributaries 
that have a significant nexus to downstream traditional navigable 
waters, interstate waters, or the territorial seas. In addition, the 
SAB suggested that EPA reconsider whether flow-through lentic systems 
should be included as ``adjacent waters'' and wetlands, rather than as 
tributaries.
    Regarding ``adjacent waters'' and wetlands, the SAB stated, ``[t]he 
available science supports the EPA's proposal to include ``adjacent 
waters'' and wetlands as a waters of the United States. . . . because 
[they] have a strong influence on the physical, chemical, and 
biological integrity of navigable waters.'' Id. In particular, the SAB 
noted, ``the available science supports defining adjacency or 
determination of adjacency on the basis of functional relationships,'' 
rather than ``solely on the basis of geographical proximity or distance 
to jurisdictional waters.'' Id. at 2-3. The agencies have determined 
which waters are adjacent, and thus jurisdictional under the rule, 
based on both functional relationships and proximity because those 
factors identify the waters that have a strong influence on the 
chemical, physical, or biological integrity of traditional navigable 
waters, interstate waters, or the territorial seas. Section C. and IV.F 
below. The agencies' determination is informed by the science, and 
consideration of proximity is reasonable in interpreting the scope of 
adjacency.
    In the evaluation of ``other waters,'' the SAB found that 
``scientific literature has established that `other waters' can 
influence downstream waters, particularly when considered in 
aggregate.'' Id. at 3. The SAB thus found it ``appropriate to define 
`other waters' as waters of the United States on a case-by-case basis, 
either alone or in combination with similarly situated waters in the 
same region.'' Id. The SAB found that distance could not be the sole 
indicator used to evaluate the connection of ``other waters'' to 
jurisdictional waters. The agencies' identification of the areas within 
which a water is assessed on a case-specific basis for a significant 
nexus is informed by the science and the agencies' experience and 
technical expertise, and consideration of proximity is reasonable in 
interpreting the scope of the statute. The SAB also expressed support 
for language in one of the options discussed in the preamble to the 
proposed rule. Specifically, the SAB stated there is ``also adequate 
scientific evidence to support a determination that certain 
subcategories and types of `other waters' in particular regions of the 
United States (e.g., Carolina and Delmarva Bays, Texas coastal prairie 
wetlands, prairie potholes, pocosins, western vernal pools) are 
similarly situated (i.e., they have a similar influence on the 
chemical, physical, and biological integrity of downstream waters and 
are similarly situated on the landscape) and thus could be considered 
waters of the United States.'' Id. The Board noted that other sets of 
wetlands could be identified as ``similarly situated'' as the science 
continues to develop and that science does not support excluding groups 
of ``other waters'' or subcategories thereof from jurisdiction.
    The exclusions paragraph of the proposed rule generated the most 
comments from the SAB. The SAB noted, ``[t]he Clean Water Act 
exclusions of groundwater and certain other exclusions listed in the 
proposed rule and the current regulation do not

[[Page 37065]]

have scientific justification.'' Id. With regard to ditches, the Board 
found that there is a lack of scientific knowledge to determine whether 
ditches should be categorically excluded. For example, some ditches 
that would be excluded in the Midwest may drain Cowardin wetlands and 
may provide certain ecosystem services, while gullies, rills, and non-
wetland swales can be important conduits for moving water between 
jurisdictional waters. The SAB also noted that artificial lakes or 
ponds, or reflection pools, can be directly connected to jurisdictional 
waters via either shallow or deep groundwater. The SAB also recommended 
that the agencies clarify in the preamble to the final rule that 
``significant nexus'' is a legal term, not a scientific one.

C. Significant Nexus Conclusions

    As noted earlier, the agencies interpret the scope of ``waters of 
the United States'' protected under the CWA based on the information 
and conclusions in the Science Report, other relevant scientific 
literature, the Technical Support Document that provides additional 
legal and scientific discussion for issues raised in this rule, the 
relevant Supreme Court decisions, the agencies' technical expertise and 
experience, and the objectives and requirements of the CWA. In light of 
this information, the agencies made scientifically and technically 
informed judgments about the nexus between the relevant waters and the 
significance of that nexus and conclude that ``tributaries'' and 
``adjacent waters,'' each as defined by the rule, have a significant 
nexus such that they are ``waters of the United States'' and no 
additional analysis is required. The agencies also determined that 
additional waters may, on a case-specific basis, have a significant 
nexus to traditional navigable waters, interstate waters, and the 
territorial seas, either alone or in combination with similarly 
situated waters. The agencies' interpretation of the scope of ``waters 
of the United States'' is informed by the Science Report and the review 
and comments of the SAB. The rule reflects the judgment of the agencies 
in balancing the science, the agencies' expertise, and the regulatory 
goals of providing clarity to the public while protecting the 
environment and public health, consistent with the law.
    Since the Rapanos decision, the agencies have gained extensive 
experience making significant nexus determinations, and that experience 
and expertise has informed the judgment of the agencies as reflected in 
the provisions of the rule. The agencies, most often the Corps, have 
made more than 400,000 CWA jurisdictional determinations since 2008. Of 
those, more than 120,000 are case-specific significant nexus 
determinations. The agencies made determinations in every state in the 
country, from the arid West to the tropics of Hawaii, from the 
Appalachian Mountains in the East to the lush forests of the Northwest. 
With field staff located in 38 Corps District offices and 10 EPA 
regional offices, the agencies have almost a decade of nationwide 
experience in making significant nexus determinations. These individual 
jurisdictional determinations have been made for waters ranging from an 
intermittent stream that provides flow to a drinking water source, to a 
group of floodplain wetlands in North Dakota that provide important 
protection from floodwaters to downstream communities alongside the Red 
River, 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. 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, as well as 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 and wetlands for downstream 
traditional navigable waters, interstate waters or the territorial 
seas.
    The agencies utilize many tools and many sources of information to 
help make jurisdictional determinations, including U.S. Geological 
Survey (USGS) and state and local topographic maps, aerial photography, 
soil surveys, watershed studies, scientific literature and references, 
and field work. 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 tributary streams, including intermittent 
and ephemeral streams, to downstream traditional navigable waters, 
interstate waters or the territorial seas. Similarly, floodplain and 
topographic maps of federal, state and local agencies, modeling tools, 
and field observations can be used to assess how wetlands are trapping 
floodwaters that might otherwise affect 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 evaluations of significant nexus. In addition, the 
agencies have experience and expertise for decades prior to and since 
the SWANCC and Rapanos decisions with making jurisdictional 
determinations, and consider hydrology, ordinary high water mark, 
biota, and other technical factors in implementing Clean Water Act 
programs. This immersion in the science along with the practical 
expertise developed through case-specific determinations across the 
country and in diverse settings is reflected in the agencies' 
conclusions with respect to waters that have a significant nexus, as 
well as where the agencies have drawn boundaries demarking where 
``waters of the United States'' end.
1. Scope of Significant Nexus Analysis
    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. Several 
terms in this standard were not defined. In this rule the agencies 
interpret these terms and the scope of ``waters of the United States'' 
based on the goals, objectives, and policies of the statute, the 
scientific literature, the Supreme Court opinions, and the agencies' 
technical expertise and experience. Therefore, for purposes of a 
significant nexus analysis, the agencies have determined (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. These determinations underpin many of 
the key elements of the rule and are reflected in the definition of 
``significant nexus'' in the rule.
a. Similarly Situated Waters
    As reflected in the rule's definition of ``significant nexus,'' the 
agencies determined that it is reasonable to consider waters as 
``similarly situated'' where they function alike and are sufficiently 
close to function together in affecting the nearest traditional

[[Page 37066]]

navigable water, interstate water, or the territorial sea. Since the 
focus of the significant nexus standard is on protecting and restoring 
the chemical, physical, and biological integrity of the nation's 
waters, the agencies interpret the phrase ``similarly situated'' in 
terms of whether particular waters are providing common, or similar, 
functions for downstream waters such that it is reasonable to consider 
their effect together. Regarding covered tributaries and covered 
adjacent waters, the agencies define each water type such that the 
functions provided are similar and the waters are situated so as to 
provide those functions together to affect downstream waters.
    The science demonstrates that covered tributaries provide many 
common vital functions important to the chemical, physical, and 
biological integrity of downstream waters, regardless of the size of 
the tributaries. The science also supports the conclusion that 
sufficient volume, duration, and frequency of flow are required to 
create a bed and banks and ordinary high water mark. The science also 
supports the conclusion that tributaries function together to affect 
downstream waters. The agencies conclude that covered tributaries with 
a bed and banks and ordinary high water mark are similarly situated for 
purposes of the agencies' significant nexus analysis.
    For covered adjacent waters, the science demonstrates that these 
waters provide many similar vital functions to downstream waters, and 
the agencies defined ``adjacent waters'' with distance boundaries to 
ensure that the waters are providing similar functions to downstream 
waters and that the waters are located comparably in the region such 
that the agencies' reasonably judged them to be similarly situated.
    For waters for which a case-specific significant nexus 
determination is required the agencies have determined that some waters 
in specific regions are similarly situated; for other specified waters, 
the determination of whether there are any other waters providing 
similar functions in a similar situation in the region must be made as 
part of a case-specific determination. See section IV.H.
    Assessing the functions of identified waters in combination is 
consistent not only with Justice Kennedy's significant nexus standard, 
but with the science. Scientists routinely combine the effects of 
groups of waters, aggregating the known effect of one water with those 
of ecologically similar waters in a specific geographic area, or to a 
certain scale. This is because the chemical, physical, and biological 
integrity of downstream waters is directly related to the aggregate 
contribution of upstream waters that flow into them, including any 
tributaries and connected wetlands. As a result, the scientific 
literature and the Science Report consistently document that the health 
of larger downstream waters is directly related to the aggregate health 
of waters located upstream, including waters such as wetlands that may 
not be hydrologically connected but function together to ameliorate the 
potential impacts of flooding and pollutant contamination from 
affecting downstream waters. See Technical Support Document.
    For example, excess nutrients discharged into small tributary 
streams in the aggregate can cause algal blooms downstream that reduce 
dissolved oxygen levels and increase turbidity in traditional navigable 
waters, interstate waters, and the territorial seas. Water low in 
dissolved oxygen cannot support aquatic life. This widely-recognized 
phenomenon, known as hypoxia, has impacted commercial and recreational 
fisheries in the northern Gulf of Mexico. In this instance, the 
cumulative effects of nutrient export from the many small headwater 
streams of the Mississippi River have resulted in large-scale 
ecological and economically harmful impacts hundreds of miles 
downstream. See Technical Support Document.
    In review of the scientific and technical adequacy of the rule, the 
SAB panel members ``generally agreed that aggregating `similarly 
situated' waters is scientifically justified, given that the combined 
effects of these waters on downstream waters are often only measurable 
in aggregate.'' \10\ As stated in section III.B. above, one of the main 
conclusions of the Science Report is that the incremental contributions 
of individual streams and wetlands are cumulative across entire 
watersheds, and their effects on downstream waters should be evaluated 
within the context of other streams and wetlands in that watershed. For 
example, the Science Report finds, ``[t]he amount of nutrients removed 
by any one stream over multiple years or by all headwater streams in a 
watershed in a given year can have substantial consequences for 
downstream waters.'' Science Report at 1-11. Cumulative effects of 
streams, wetlands, and open waters across a watershed must be 
considered because ``[t]he downstream consequences (e.g., the amount 
and quality of materials that eventually reach a river) are determined 
by the aggregate effect of contributions and sequential alterations 
that begin at the source waters and function along continuous flowpaths 
to the watershed outlet.'' Id. at 1-19.
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    \10\ September 2, 2014. Memorandum from Dr. Amanda Rodewald to 
Dr. David Allen. Comments to the chartered SAB on the Adequacy of 
the Scientific and Technical Basis of the EPA's Proposed Rule titled 
``Definition of `Waters of the United States' under the Clean Water 
Act.'' (``SAB 2014c.'')
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    The agencies conclude that it is appropriate to assess the effects 
of waters in combination based on the similarity of the functions they 
provide to the downstream water and their location in the watershed. 
This is consistent with the science and effectively meets the goals of 
the CWA.
b. In the Region
    Since Justice Kennedy did not define the ``region,'' the agencies 
determined that the single point of entry watershed is a reasonable and 
technically appropriate scale for identifying ``in the region'' for 
purposes of the significant nexus standard. A single point of entry 
watershed is the drainage basin within whose boundaries all 
precipitation ultimately flows to the nearest single traditional 
navigable water, interstate water, or the territorial sea. The agencies 
determined that because the movement of water from watershed drainage 
basins to coastal waters, river networks, and lakes shapes the 
development and function of these systems in a way that is critical to 
their long-term health, the watershed is a reasonable and technically 
appropriate way to identify the scope of waters that together may have 
an effect on the chemical, physical, or biological integrity of a 
particular traditional navigable water, interstate water, or 
territorial sea. The watershed includes all streams, wetlands, lakes, 
and open waters within its boundaries. Using the watershed that flows 
to the nearest single traditional navigable water, interstate water, or 
territorial sea is consistent with court decisions that these waters 
are the ultimate focus of CWA protections. Using the single point of 
entry watershed ensures that any analysis of significant nexus is 
appropriately connected to these touchstone waters.
    Because the movement of water from watershed drainage basins to 
coastal waters, river networks, and lakes shapes the development and 
function of these systems in a way that is critical to their integrity, 
using a watershed as the framework for conducting significant nexus 
evaluations is scientifically supportable. Watersheds are generally 
regarded as the most appropriate spatial unit for water resource 
management. Anthropogenic actions and natural events can have 
widespread effects within the watershed that collectively

[[Page 37067]]

impact the integrity and quality of the relevant traditional navigable 
water, interstate water, or the territorial sea. The functions of the 
contributing waters are inextricably linked and have a cumulative 
effect on the integrity of the downstream traditional navigable water, 
interstate water, or the territorial sea. For these reasons, it is more 
appropriate to conduct a significant nexus analysis at the watershed 
scale than to focus on a specific site, such as an individual stream 
segment. See proposal Appendix A, Scientific Analysis, 79 FR 22246, 
April 21, 2014, Science Report, and Technical Support Document.
    Concluding that the watershed is the reasonable and appropriate 
region for purposes of a significant nexus analysis is also consistent 
with the agencies' longstanding practice and experience. To restore or 
maintain the health of the downstream affected water, the agencies' 
standard practice is to evaluate the condition of the waters that are 
in the contributing watersheds and to develop a plan to address the 
issues of concern. The Corps has used watershed framework approaches 
for water sources, for navigation approaches for more than 100 years, 
and in the regulatory program since its inception. Also, using a 
watershed framework is consistent with more than two decades of 
practice by EPA and many other governmental, academic, and additional 
entities that recognize that a watershed approach is the most effective 
framework to address water resource challenges. Finally, the watershed 
that drains to the nearest (i.e., first downstream) traditional 
navigable water, interstate water, or the territorial seas is likely to 
be of a size commonly understood as a ``region.''
    In light of the scientific literature, the longstanding approach of 
the agencies' implementation of the CWA, and the statutory goals 
underpinning Justice Kennedy's significant nexus framework, the 
watershed draining to the nearest traditional navigable water, 
interstate water, or the territorial sea, is the appropriate ``region'' 
for a significant nexus analysis. See the proposed rule preamble and 
Technical Support Document.
c. Significantly Affect Chemical, Physical, or Biological Integrity
    The agencies' definition of the term ``significant nexus'' in the 
rule is consistent with language in Riverside Bayview, SWANCC, and 
Rapanos, and with the goals, objectives, and policies of the CWA. The 
definition reflects that not all waters have a requisite connection to 
traditional navigable waters, interstate waters, or the territorial 
seas sufficient to be determined jurisdictional. Justice Kennedy was 
clear that to be covered, waters must significantly affect the 
chemical, physical, or biological integrity of a downstream navigable 
water and that the requisite nexus must be more than ``speculative or 
insubstantial,'' Rapanos, at 780. The agencies define significant nexus 
in precisely those terms. Under the rule a ``significant nexus'' is 
established by a showing of a significant chemical, physical, or 
biological effect. In characterizing the significant nexus standard, 
Justice Kennedy stated: ``[t]he required nexus must be assessed in 
terms of the statute's goals and purposes. Congress enacted the [CWA] 
to `restore and maintain the chemical, physical, and biological 
integrity of the Nation's waters'. . . .'' 547 U.S. at 779. It is clear 
that Congress intended the CWA 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 
subvert the objective if the CWA 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.
    In the rule's definition of ``significant nexus,'' the agencies 
identify the functions that waters provide that can significantly 
affect the chemical, physical, or biological integrity of traditional 
navigable waters, interstate waters and the territorial seas. In 
identifying the functions to be considered the agencies were informed 
by the goals of the statute and the available science. Among the means 
to achieve the CWA's objective to restore and maintain the chemical, 
physical, and biological integrity of the Nation's waters, Congress 
established an interim national goal to achieve wherever possible 
``water quality which provides for the protection and propagation of 
fish, shellfish, and wildlife and provides for recreation in and on the 
water.'' Section 101(a)(2). Functions to be considered for the purposes 
of determining significant nexus are sediment trapping; nutrient 
recycling; pollutant trapping, transformation, filtering, and 
transport; retention and attenuation of floodwaters; runoff storage; 
contribution of flow; export of organic matter; export of food 
resources; and provision of life-cycle dependent aquatic habitat (such 
as foraging, feeding, nesting, breeding, spawning, and use as a nursery 
area) for species located in traditional navigable waters, interstate 
waters, or the territorial seas. The effect of an upstream water can be 
significant even when a water, alone or in combination, is providing a 
subset, or even just one, of the functions listed.
    Science demonstrates that these aquatic functions provided by 
smaller streams, ponds, wetlands and other waters are important for 
protecting the chemical, physical, and biological integrity of 
downstream traditional navigable waters, interstate waters, and the 
territorial seas. For example, States identify sediment and nutrients 
as the primary contaminants in the nation's waters. Sediment storage 
and export via streams to downstream waters is critical for maintaining 
the river network, including the formation of channel features. 
Although sediment is essential to river systems, excess sediment can 
impair ecological integrity by filling interstitial spaces, reducing 
channel capacity, blocking sunlight transmission through the water 
column, and increasing contaminant and nutrient concentrations. Streams 
and wetlands can prevent excess deposits of sediment downstream and 
reduce pollutant concentrations in downstream waters. Thus the function 
of trapping of excess sediment, along with export of sediment, have a 
significant effect on the chemical, physical, and biological integrity 
of downstream waters.
    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 nutrient loads 
and associated impairments due to excess nutrients in downstream 
waters. Streams, wetlands and open waters improve water quality through 
the assimilation, transformation, or sequestration of pollutants, 
including excess nutrients and chemical contaminants such as pesticides 
and metals that can degrade downstream water integrity. Nutrient 
transport exports nutrients downstream and can degrade water quality 
and lead to stream impairments. Nutrients are necessary to support 
aquatic life, but excess nutrients lead to excessive plant growth and 
hypoxia, in which over-enrichment causes dissolved oxygen 
concentrations to fall below the level necessary to sustain most 
aquatic animal life in the downstream waters. Nutrient recycling, 
retention, and export can significantly affect downstream chemical 
integrity by impacting downstream water quality.
    The contribution of flow downstream is an important role, as 
upstream waters can be a cumulative source of the majority of the total 
mean annual flow to bigger downstream rivers and waters, including via 
the recharge of baseflow.

[[Page 37068]]

Streams, wetlands, and open waters contribute surface and subsurface 
water downstream, and are the dominant sources of water in most rivers. 
Contribution of flow can significantly affect the physical integrity of 
downstream waters, helping to sustain the volume of water in larger 
waters.
    Small streams and wetlands are particularly effective at retaining 
and attenuating floodwaters. By subsequently releasing 
(desynchronizing) floodwaters and retaining large volumes of stormwater 
that could otherwise negatively affect the condition or function of 
downstream waters, streams and adjacent wetlands and open waters affect 
the physical integrity of downstream traditional navigable waters, 
interstate waters, or the territorial seas. This function can reduce 
flood peaks downstream and can also maintain downstream river baseflows 
by recharging alluvial aquifers.
    Streams, wetlands, and open waters supply downstream waters with 
dissolved and particulate organic matter (e.g., leaves, wood), which 
support biological activity throughout the river network. In addition 
to organic matter, streams, wetlands, and open waters can also export 
other food resources downstream, such as aquatic insects that are the 
food source for fish in downstream waters. The export of organic matter 
and food resources downstream is important to maintaining the food webs 
and thus the biological integrity of traditional navigable waters, 
interstate waters, and the territorial seas.
    Streams, wetlands, and open waters provide life-cycle dependent 
aquatic habitat (such as foraging, feeding, nesting, breeding, 
spawning, and use as a nursery area) for species located in traditional 
navigable waters, interstate waters, or the territorial seas. Many 
species require different habitats for different resources (e.g., food, 
spawning habitat, overwintering habitat), and thus move throughout the 
river network over their life-cycles. For example, headwater streams 
can provide refuge habitat under adverse conditions, enabling fish to 
persist and recolonize downstream areas once conditions have improved. 
These upstream systems form integral components of downstream food 
webs, providing nursery habitat for breeding fish and amphibians, 
colonization opportunities for stream invertebrates, and maturation 
habitat for stream insects, including for species that are critical to 
downstream ecosystem function. The provision of life-cycle dependent 
aquatic habitat for species located in downstream waters significantly 
affects the biological integrity of those downstream waters.
    Tributaries, adjacent wetlands, and open waters can perform 
multiple functions, including functions that change depending upon the 
season. For example, the same stream can contribute flow when 
evapotranspiration is low and can retain water when evapotranspiration 
is high. These functions, particularly when considered in aggregate 
with the functions of similarly situated waters in the region, can 
significantly affect the chemical, physical, or biological integrity of 
a traditional navigable water, interstate water, or the territorial 
seas. When considering the effect of an individual stream, wetland, or 
open water, all contributions and functions that the water provides 
should be evaluated cumulatively. For example, the same wetland retains 
sediment, removes excess nutrients, mitigates flooding, and provides 
habitat for amphibians that also live downstream; if any of these 
functions is ignored, the overall effect of that wetland would be 
underestimated. It is important to note, however, that a water or 
wetland can provide just one function that may significantly affect the 
chemical, physical or biological integrity of the downstream water.
2. Categories of Waters Determined to Have a Significant Nexus
    In this rule, the agencies determine that: (1) Covered tributaries, 
in combination with other covered tributaries located in a watershed 
that drains to a traditional navigable water, interstate water, or the 
territorial seas, significantly affect the chemical, physical, and 
biological integrity of that water; and (2) covered adjacent waters, in 
combination with other covered adjacent waters located in a watershed 
that drains to a traditional navigable water, interstate water, or the 
territorial seas, significantly affect the chemical, physical, and 
biological integrity of that water.
a. Covered Tributaries
    The agencies determine based on their scientific and technical 
expertise that waters meeting the definition of ``tributary'' in a 
single point of entry watershed are similarly situated and have a 
significant nexus because they significantly affect the chemical, 
physical, or biological integrity of traditional navigable waters, 
interstate waters, and the territorial seas. As such, it is appropriate 
to conclude covered tributaries as a category are ``waters of the 
United States.'' See Technical Support Document. The agencies limited 
the tributaries that are ``waters of the United States'' to those that 
have both a bed and banks and another indicator of ordinary high water 
mark. That limitation served as a reasonable basis to consider covered 
tributaries similarly situated because those physical characteristics 
indicated sufficient flow that the covered tributaries are performing 
similar functions and located such that they are working together in 
the region to provide those functions to the nearest traditional 
navigable water, interstate water, or the territorial seas. Justice 
Kennedy noted that the requirement of a perceptible ordinary high water 
mark for tributaries, a measure that had been used by the Corps, ``may 
well provide a reasonable measure of whether specific minor tributaries 
bear a sufficient nexus with other regulated waters to constitute 
`navigable waters' under the Act.'' 547 U.S. at 781, see also id. at 
761. The science supports this.
    The agencies analyzed the Science Report and other scientific 
literature to determine whether tributaries to traditional navigable 
waters, interstate waters, or the territorial seas have a significant 
nexus to constitute ``waters of the United States'' under the Act such 
that it is reasonable to assert CWA jurisdiction over all such 
tributaries by rule. Covered tributaries have a significant impact on 
the chemical, physical, or biological integrity of waters into which 
they eventually flow--for CWA purposes, traditional navigable waters, 
interstate waters, and the territorial seas. The great majority of 
covered tributaries are headwater streams, and whether they are 
perennial, intermittent, or ephemeral, they play an important role in 
the transport of water, sediments, organic matter, nutrients, and 
organisms to downstream waters. Covered tributaries serve to store 
water, thereby reducing flooding; provide biogeochemical functions that 
help maintain water quality; trap and transport sediments; transport, 
store and modify pollutants; provide habitat for plants and animals; 
and sustain the biological productivity of downstream rivers, lakes, 
and estuaries. Such waters have these significant effects whether they 
are natural, modified, or constructed.
    Covered tributaries significantly affect the chemical integrity of 
traditional navigable waters, interstate waters, and the territorial 
seas. Covered tributaries influence the chemical composition of 
downstream waters, through the transport and removal of chemical 
elements and compounds, such as nutrients, ions, organic matter and 
pollutants. Ecosystem processes in

[[Page 37069]]

covered tributaries transform, remove, and transport these substances 
to downstream waters. In turn, these chemical compounds can influence 
water quality, sediment deposition, nutrient availability, and biotic 
functions in rivers. Because water flow transports chemical substances 
downstream, chemical effects are closely related to hydrological 
connectivity. Within covered tributaries, there are processes that 
occur that transform and export nutrients and carbon to downstream 
waters, serving important source functions that influence the chemical 
integrity of downstream waters. Organic carbon, in both dissolved and 
particulate forms, exported from covered tributaries is consumed by 
downstream organisms. The organic carbon that is exported downstream 
thus supports biological activity throughout the river network.
    Covered tributaries act as both sinks and sources of chemical 
substances, further affecting the chemical integrity of traditional 
navigable waters, interstate waters, and the territorial seas. Covered 
tributaries provide sink functions by trapping chemicals through 
absorption to sediments in the stream substrate (e.g., phosphorous 
adsorption to clay particles). They provide source functions by 
transporting chemicals to downstream traditional navigable waters, 
interstate waters, and the territorial seas as chemicals dissolved in 
the waters or as chemicals attached to suspended sediments.
    Covered tributaries significantly affect the physical integrity of 
traditional navigable waters, interstate waters, and the territorial 
seas. Physical connections between covered tributaries and traditional 
navigable waters, interstate waters, and the territorial seas result 
from the hydrologic transport from covered tributaries to downstream 
waters of numerous materials, including water, sediment and organic 
matter such as leaves and wood. This transport affects the physical 
characteristics of downstream waters. Covered tributaries, even when 
seasonally dry, are the dominant source of water in most rivers, rather 
than direct precipitation or groundwater input to main stem river 
segments. One of the primary functions of covered tributaries is 
transporting sediment to downstream waters. Covered tributaries, 
particularly headwaters, shape and maintain river channels by 
accumulating and gradually or episodically releasing sediment and large 
woody debris into river channels. These effects occur even when the 
covered tributaries flow infrequently (such as ephemeral covered 
tributaries), and even when the covered tributaries are great distances 
from the traditional navigable water, interstate water, or the 
territorial sea (such as some headwater covered tributaries).
    Covered tributaries significantly affect the biological integrity 
of traditional navigable waters, interstate waters, and the territorial 
seas. Covered tributaries, including intermittent and ephemeral 
streams, are critical in the life-cycles of many organisms capable of 
moving throughout river networks. In fact, many organisms, such as 
anadromous salmon, have complex life-cycles which involve migration 
through the river network, from headwaters to downstream rivers and 
oceans and back, over the course of their lives. In addition to 
providing critical habitat for complex life-cycle completion, covered 
tributaries provide refuge from predators and adverse physical 
conditions in rivers, and are reservoirs of genetic- and species-level 
diversity. Covered tributaries contribute materials to downstream food 
networks and supporting populations for aquatic species, including 
economically important species such as salmon. These effects occur even 
when the covered tributaries flow infrequently (such as ephemeral 
covered tributaries), and even when the covered tributaries are large 
distances from the traditional navigable waters, interstate waters, and 
the territorial seas (such as some headwater covered tributaries).
    Similarly, modified and constructed tributaries perform the same 
functions as natural tributaries, especially the conveyance of water 
that carries nutrients, pollutants, and other constituents, both good 
and bad, to traditional navigable waters, interstate waters, and the 
territorial seas. Modified and constructed covered tributaries also 
provide corridors for movement of organisms between headwaters and 
traditional navigable waters, interstate waters, and the territorial 
seas. The important effect--and thus the significant nexus--between a 
covered tributary and a traditional navigable water, interstate water, 
and the territorial sea is not broken where the covered tributary flows 
through a culvert or other structure. The scientific literature 
recognizes that features that convey water, whether they are natural, 
modified, or constructed, provide substantial connectivity between 
streams and downstream waters. For example, ditches that meet the 
definition of tributary and are not excluded quickly move water 
downstream to traditional navigable waters, interstate waters, and the 
territorial seas due to their often straightened and channelized 
nature, transporting downstream sediment, nutrients, and other 
materials.
    The CWA regulates and controls pollution at its source, in part 
because most pollutants do not remain at the site of the discharge, but 
instead flow and are washed downstream through the tributary system to 
endanger drinking water supplies, fisheries, and recreation areas. 
These fundamental facts about the movement of pollutants and the 
interconnected nature of the tributary system demonstrate why covered 
tributaries of traditional navigable waters, interstate waters, and the 
territorial seas, alone or in combination with other covered 
tributaries in a watershed, have a significant nexus with those 
downstream waters. Thus, in the rule the agencies assert CWA 
jurisdiction over all covered tributaries as defined. Those covered 
tributaries are ``waters of the United States'' without the need for 
further analysis.
b. Covered Adjacent Waters
    Based on the agencies' review of the scientific literature and the 
law, the agencies determine that covered adjacent waters, as defined, 
have a significant nexus and are ``waters of the United States.'' The 
scientific literature, including the Science Report, consistently 
supports the conclusion that covered adjacent waters provide similar 
functions and work together to maintain the chemical, physical, and 
biological integrity of the downstream traditional navigable waters, 
interstate waters, and the territorial seas because of their 
hydrological and ecological connections to, and interactions with, 
those waters. Science demonstrates that this functional connectivity is 
particularly evident where covered adjacent waters are located within 
the floodplain of the traditional navigable water, interstate water, 
the territorial seas, covered tributary, or impoundment to which they 
are adjacent or are otherwise sufficiently proximate to waters with no 
floodplain, such as lakes and ponds. Location within the floodplain and 
proximity ensure that the aquatic functions performed by covered 
adjacent waters are effectively and consistently provided to downstream 
waters. See Technical Support Document.
    The agencies conclude that all waters meeting the definition of 
``adjacent'' in the rule are similarly situated for purposes of 
analyzing whether they have a significant nexus to a traditional 
navigable water, interstate water, or the territorial sea. Based on a 
review of the scientific literature, the agencies conclude that these 
bordering, contiguous, or neighboring waters

[[Page 37070]]

provide similar functions and function together to significantly affect 
the chemical, physical, or biological integrity of traditional 
navigable waters, interstate waters, or the territorial seas. Further, 
because the definition of ``adjacent'' considers both the functional 
relationships and the proximity of the waters (i.e., those that are 
located near traditional navigable waters, interstate waters, the 
territorial seas, impoundments, and covered tributaries), interpreting 
the term ``similarly situated'' to include all covered adjacent waters, 
as defined in the rule, is informed by the science and is a reasonable 
interpretation of the scope of the statute. The geographic proximity of 
an ``adjacent'' water relative to the traditional navigable waters, 
interstate waters, the territorial seas, impoundments, and covered 
tributaries is indicative of the relationship to it, with many of its 
defining characteristics resulting from the movement of materials and 
energy between the categories of waters. The scientific literature 
supports that waters, including wetlands, ponds, lakes, oxbow lakes, 
and similar waters, that are ``adjacent,'' as defined in the rule, to 
traditional navigable waters, interstate waters, the territorial seas, 
impoundments, and covered tributaries, are integral parts of stream 
networks because of their ecological functions and how they interact 
with each other, and with downstream traditional navigable waters, 
interstate waters, or the territorial seas.
    Covered adjacent waters function together to maintain the chemical, 
physical, or biological health of traditional navigable waters, 
interstate waters, and the territorial seas to which they are directly 
adjacent or to which they are connected by the tributary system. This 
functional interaction can result from hydrologic connections or 
because covered adjacent waters can act as water storage areas holding 
damaging floodwaters or filtering harmful pollutants. These chemical, 
physical, and biological connections affect the integrity of downstream 
traditional navigable waters, interstate waters, and the territorial 
seas through the temporary storage and deposition of channel-forming 
sediment and woody debris, temporary storage of local groundwater 
sources of baseflow for downstream waters and their tributaries, and 
transformation and transport of organic matter. Covered adjacent waters 
improve water quality through the assimilation, transformation, or 
sequestration of pollutants, including excess nitrogen and phosphorus, 
and chemical contaminants such as pesticides and metals that can 
degrade downstream water integrity. In addition to providing effective 
buffers to protect downstream waters from pollution, covered adjacent 
waters form integral components of downstream food webs, providing 
nursery habitat for breeding fish and amphibians, colonization 
opportunities for stream invertebrates, and maturation habitat for 
stream insects. Covered adjacent waters serve an important role in the 
integrity of traditional navigable waters, interstate waters, and the 
territorial seas by subsequently releasing (desynchronizing) 
floodwaters and retaining large volumes of stormwater, sediment, 
nutrients, and contaminants that could otherwise negatively impact the 
condition or function of traditional navigable waters, interstate 
waters, and the territorial seas.
    Floodplain areas connect aquatic environments through both surface 
and shallow subsurface hydrologic flowpaths. Waters in these areas are 
therefore uniquely situated in watersheds to receive and process water 
that passes over densely vegetated areas and through subsurface zones 
before reaching streams and rivers. When contaminants reach a 
floodplain water, they can be sequestered in sediments, assimilated 
into wetland plants and animals, transformed into less harmful and/or 
mobile forms or compounds, or lost to the atmosphere. Wetlands located 
in floodplains store large amounts of sediment and organic matter from 
upstream and upland areas. In addition, the primary function of many 
floodplain wetlands in the Western United States is sediment exchange, 
which can transform materials and compounds temporarily on floodplains.
    Wetlands and other similar waters in floodplain areas act as 
buffers that are among the most effective tools for mitigating nonpoint 
source pollution. The literature shows that collectively, wetlands and 
other similar waters improve water quality through assimilation, 
transformation, or sequestration of nutrients, sediment, and other 
pollutants--such as pesticides and metals--that can affect downstream 
water quality. These pollutants enter floodplain wetlands from dry and 
wet atmospheric deposition, runoff from upland agricultural and urban 
areas, spray drift, subsurface water flows, outfalls, pipes, and 
ditches.
    Floodplain waters, including wetlands, can reduce flood peaks by 
storing and desynchronizing floodwaters. They can also maintain river 
baseflows by recharging alluvial aquifers. Many studies have documented 
the ability of floodplain wetlands to reduce flood pulses by storing 
excess water from streams and rivers. One review of wetland studies 
reported that floodplain wetlands reduced or delayed floods in 23 of 28 
studies. For example, peak discharges between upstream and downstream 
gaging stations on the Cache River in Arkansas were reduced 10-20 
percent primarily due to floodplain water storage.
    Ecosystem function within a river system is driven by interactions 
between the physical environment and the diverse biological communities 
living within the river system. Wetlands in floodplains become 
important seed sources for the river network, especially if 
catastrophic flooding scours vegetation and seed banks in other parts 
of the channel. Movements of organisms that connect aquatic habitats 
and their populations, even across different watersheds, are important 
for the survival of individuals, populations, and species, and for the 
functioning of the river ecosystem. For example, lateral expansion and 
contraction of the river in its floodplain results in an exchange of 
matter and organisms, including fish populations that are adapted to 
use floodplain habitat for feeding and spawning during high water. The 
organisms that live within the hyporheic zone for these mid- and large-
sized river systems have a demonstrated connection outward to several 
miles within the floodplain. General field practice observations 
further indicate that covered adjacent waters with a close proximity 
have a significant nexus with the downstream waters.
    Waters adjacent to impoundments and covered tributaries are 
integrally linked to the chemical, physical, and biological functions 
of the waters to which they are adjacent and, through those waters, are 
integrally linked to the chemical, physical, and biological functions 
of the downstream traditional navigable waters, interstate waters, or 
the territorial seas. Thus, where waters are adjacent to impoundments 
or covered tributaries, they also have a significant nexus to the 
downstream traditional navigable waters, interstate waters, or the 
territorial seas. The important functions that covered adjacent waters 
perform that impact downstream traditional navigable waters, interstate 
waters, and the territorial seas and their integrated behavior with the 
tributary system demonstrate why all waters adjacent to traditional 
navigable waters, interstate waters, or the territorial seas as well as 
impoundments and covered tributaries, alone or in combination with 
other

[[Page 37071]]

covered adjacent wetlands in a watershed have a significant nexus with 
those downstream waters.
    Based on the science and their technical expertise and experience, 
the agencies determine it is appropriate to protect all covered 
adjacent waters because those waters are functioning as an integrated 
system with the downstream traditional navigable waters, interstate 
waters, or the territorial seas and significantly affect such 
downstream waters. Consequently, these waters are ``adjacent'' and 
therefore ``waters of the United States'' under the CWA. Covered 
adjacent waters are ``waters of the United States'' without the need 
for further analysis.
3. Case-Specific Significant Nexus Determinations
a. Two Exclusive Circumstances for Case-Specific Significant Nexus 
Determinations
    The rule identifies two exclusive circumstances under which a 
significant nexus determination is made on a case-specific basis to 
determine whether the water is a ``water of the United States.'' First, 
there are five subcategories of waters--Prairie potholes, Carolina and 
Delmarva bays, pocosins, western vernal pools in California, and Texas 
coastal prairie wetlands--that the agencies conclude must be analyzed 
``in combination'' as ``similarly situated '' waters when making a 
case-specific significant nexus analysis. Second, there are waters for 
which the agencies have made no conclusions with respect to which 
waters are ``similarly situated'' but for which a case-specific 
significant nexus analyses may be undertaken. The rule establishes that 
case-specific determinations may be made for waters located within the 
100-year floodplain of a traditional navigable water, interstate water, 
or the territorial seas, and for waters located within 4,000 feet from 
the high tide line or the ordinary high water mark of traditional 
navigable waters, interstate waters, the territorial seas, 
impoundments, or tributaries.
b. Summary of Rationale for ``Similarly Situated'' Determinations
    Based on the agencies' expertise and experience and available 
literature and data, the agencies have determined that waters in the 
five subcategories of waters identified in paragraph (a)(7) are 
similarly situated and must be combined with other waters in the same 
subcategory located in the same watershed that drains to the nearest 
traditional navigable water, interstate water, or the territorial seas. 
See Technical Support Document. The scientific literature shows that 
these subcategories of waters are frequently located together in a 
complex or are otherwise closely co-located and perform similar 
functions. The agencies specifically sought comment in the proposal on 
options to address these five subcategories of waters, including 
whether waters in these subcategories should be found ``similarly 
situated'' by rule.
    Based on the body of scientific literature regarding the 
subcategories of waters specified in paragraph (a)(7) and their 
functions, the agencies determined that waters of the specified 
subcategories are similarly situated because they perform similar 
functions and they are located sufficiently close to each other to 
function together in affecting downstream waters and therefore 
reasonably be evaluated in combination with regard to their effects on 
the integrity of traditional navigable waters, interstate waters, or 
the territorial seas. The specified subcategories of waters perform 
similar functions as waters of the same subcategory in the same single 
point of entry watershed and collectively function together to affect a 
traditional navigable water, interstate water, or the territorial seas. 
Among the functions and relationships in the landscape the agencies 
considered to conclude that the subcategories are each similarly 
situated are the physical capacity of the waters to provide flood and 
sediment retention. In determining that the waters in each of the five 
subcategories are ``similarly situated,'' the agencies concluded that 
these subcategories of waters are co-located to each other or similar 
to the tributary system such that they have cumulative and additive 
effects on pollutant removal through parallel, serial, or sequential 
processing, such as the role of pocosins in maintaining water quality 
in estuaries. The subcategories of waters are sufficiently near each 
other or the tributary system to function as an integrated habitat that 
can support the life-cycle of a species or more broadly provide habitat 
to a large number of a single species.
    The SAB expressed support for the agencies' option in the preamble 
of the proposed rule to identify certain subcategories of waters as 
similarly situated and highlighted these same five subcategories. It 
stated, ``[t]here is also adequate scientific evidence to support a 
determination that certain subcategories and types of `other waters' in 
particular regions of the United States (e.g., Carolina and Delmarva 
Bays, Texas coastal prairie wetlands, prairie potholes, pocosins, 
western vernal pools) are similarly situated (i.e., they have a similar 
influence on the physical, chemical and biological integrity of 
downstream waters and are similarly situated on the landscape) and thus 
could be considered waters of the United States. Furthermore, as the 
science continues to develop, other sets of wetlands may be identified 
as `similarly situated.' '' SAB 2014b at 3.
    The agencies concluded that the specific subcategories of waters 
listed in paragraph (a)(7) are similarly situated for purposes of a 
case-specific significant nexus based on the following:
    (i) Prairie potholes are a complex of glacially formed wetlands, 
usually occurring in depressions that lack permanent natural outlets 
that are found in the central United States and Canada. In the United 
States, they are found from central Iowa through western Minnesota, 
Montana, eastern South Dakota, and North Dakota. Prairie potholes 
demonstrate a wide range of hydrologic permanence; some hold permanent 
standing water and others are wet only in years with high 
precipitation. This in turn influences the diversity and structure of 
their biological communities.
    Prairie potholes generally accumulate and retain water effectively 
due to the low permeability of their underlying soil, which can 
modulate flow characteristics of nearby streams and rivers. One of the 
most noted hydrologic functions of Prairie potholes is water storage. 
Because most of the water outflow in Prairie potholes is via 
evapotranspiration, Prairie potholes can become water sinks, preventing 
flow to downstream waters. Prairie potholes also can accumulate 
chemicals in overland flow, thereby reducing chemical loading to other 
bodies of water. When Prairie potholes are artificially connected to 
streams and lakes through drainage, they become sources of water and 
chemicals to downstream waters. Prairie potholes also support a 
community of highly mobile organisms, from plants to invertebrates that 
move among Prairie potholes and that can biologically connect the 
entire complex to the river network.
    Prairie potholes can be highly connected to other Prairie potholes 
via shallow subsurface connections and via surface hydrologic 
connections during the wet season. They can also be connected to the 
stream network via surface and shallow subsurface connections. Intense 
precipitation events or high cumulative precipitation over one or more 
seasons can result in temporary hydrologic connectivity between Prairie 
potholes and from

[[Page 37072]]

Prairie potholes to the tributary system via ``fill-and-spill'' events.
    Their density across the landscape varies from region to region as 
the result of several factors, including patterns of glacial movement, 
topography, and climate. In some parts of the region, prairie pothole 
density is very high. Though their density varies across the landscape, 
Prairie potholes often act as a complex. They have similar functions 
that can collectively impact downstream waters.
    Prairie potholes have been determined to be similarly situated 
based on the characteristics of Prairie potholes, including their 
density on the landscape, their interaction and formation as a complex 
of wetlands and open waters, their connections to each other and the 
tributary network, and their similar functions. In addition, their 
chemical, physical, and biological connections to downstream waters and 
the strength of their effects on the chemical, physical, or biological 
integrity of a traditional navigable water, interstate water, or the 
territorial seas support this determination that Prairie potholes are 
similarly situated by rule.
    (ii) Carolina and Delmarva bays are ponded depressional wetlands 
that occur along the Atlantic coastal plain from northern Florida to 
New Jersey. Though Carolina and Delmarva bays are from the same 
category of wetland and perform similar functions, they are located in 
different parts of the Atlantic coastal plain and thus have unique 
names. Carolina bays are most abundant in North Carolina and South 
Carolina, while Carolina bays found in the Delmarva Peninsula are 
commonly referred to as Delmarva bays or Delmarva potholes.
    Most bays receive water through precipitation, lose water through 
evapotranspiration, and lack natural surface outlets. Both mineral-
based and peat-based bays have shown connections to shallow 
groundwater. Bays typically are in proximity to each other or to 
streams, providing for hydrologic connections to each other and to 
downstream waters in large rain events via overland flow or shallow 
subsurface connections. Some Delmarva bays have surface water 
connections to the Chesapeake Bay. In addition, human channeling and 
ditching of the bays are widespread and create surface connections to 
other waters, including the tributary system and estuaries. These 
ditches commonly connect the surface water of bays to other bays that 
are lower on the landscape, and ultimately, to streams.
    The hydrology in bays allow for denitrification (chemical and 
biological processes that remove nitrogen from water), which can reduce 
the amount of nitrate in both groundwater and downstream surface 
waters. Because bays are frequently connected chemically to downstream 
waters through ditches, they can be sources of sediment and nutrients 
to downstream waters. Where they are not connected via confined surface 
connections, bays can act as sediment and nutrient sinks.
    Fish are reported in bays that are known to dry out, indirectly 
demonstrating surficial connections. Amphibians and reptiles use bays 
extensively for breeding and for rearing young. These animals can 
disperse many feet on the landscape and can colonize, or serve as a 
food source to, downstream waters. Similarly, bays foster abundant 
insects that have the potential to become part of the downstream food 
chain. Humans have ditched and channelized a high percentage of bays, 
creating new surface connections to downstream waters and allowing 
transfer of nutrients, sediment, and other pollutants, such as 
methylmercury.
    Carolina and Delmarva bays can occur in high density on the 
landscape and can act as a wetlands complex. Bays have similar 
functions to other bays and cumulatively these functions can impact 
downstream waters.
    The agencies conclude that Carolina and Delmarva bays are similarly 
situated based on their close proximity to each other and the tributary 
network, their hydrologic connections to each other and the tributary 
network, their density on the landscape, and their similar functions.
    (iii) The word pocosin comes from the Algonquin Native American 
word for ``swamp on a hill,'' and these evergreen shrub and tree-
dominated wetlands are found from Virginia to northern Florida, but 
mainly in North Carolina. Typically, there is no standing water present 
in these peat-accumulating wetlands, but a shallow water table leaves 
the soil saturated for much of the year. They range in size from less 
than an acre to several thousand acres. The slow movement of water 
through the dense organic matter in pocosins removes excess nutrients 
deposited by rainwater. The same organic matter also acidifies the 
water. This water is slowly released to downstream waters and 
estuaries, where it helps to maintain the proper salinity, nutrients, 
and acidity.
    Because pocosins are the topographic high areas on the regional 
landscape, they serve as the source of water for downstream waters. 
Pocosins often have seasonal connections to drainageways leading to 
estuaries or are adjoining other wetlands draining into perennial 
streams or estuaries. Other pocosins have been ditched and are directly 
connected to streams.
    The agencies conclude that pocosins are similarly situated based on 
their close proximity to each other and the tributary network, their 
hydrologic connections to each other and the tributary network, their 
density on the landscape, and their similar functions.
    (iv) Western vernal pools are shallow, seasonal wetlands that 
accumulate water during colder, wetter months and gradually dry up 
during warmer, drier months. Western vernal pools are seasonal wetlands 
from the Pacific Northwest to northern Baja California, Mexico 
associated with topographic depressions, soils with poor drainage, 
mild, wet winters and hot, dry summers. The agencies have determined 
that California vernal pools are ``similarly situated.''
    Because their hydrology and ecology are so tightly coupled with the 
local and regional geological processes that formed them, western 
vernal pools in California typically occur within ``vernal pool 
landscapes,'' or complexes of pools in which swales connect pools to 
each other and to seasonal streams. Some common findings about the 
hydrologic connectivity of western vernal pools include evidence for 
temporary or permanent outlets, frequent filling and spilling of higher 
pools into lower elevation swales and stream channels, and conditions 
supporting subsurface flows through pools without perched aquifers to 
nearby streams.
    Non-glaciated vernal pools in western states are reservoirs of 
biodiversity and can be connected genetically to other locations and 
aquatic habitats through wind- and animal-mediated dispersal. Animals 
and other organisms can move between western vernal pool complexes and 
streams. Insects and zooplankton can be flushed from vernal pools into 
streams and other waters during periods of overflow, carried by animal 
vectors (including humans), or dispersed by wind.
    The agencies conclude that western vernal pools in California are 
similarly situated based on their close proximity to each other and the 
tributary network, their interaction and arrangement as a complex of 
wetlands, their hydrologic connections to each other and the tributary 
network, their density on the landscape, and their similar functions.
    (v) Along the Gulf of Mexico from western Louisiana to south Texas, 
freshwater wetlands occur as a mosaic

[[Page 37073]]

of depressions, ridges, intermound flats, and mima mounds. These 
coastal prairie wetlands were formed thousands of years ago by ancient 
rivers and bayous and once occupied almost a third of the landscape 
around Galveston Bay, Texas. The term Texas coastal prairie wetlands is 
not used uniformly in the scientific literature but encompasses Texas 
prairie pothole (freshwater depressional wetlands) and marsh wetlands 
that are described in some studies that occur on the Lissie and 
Beaumont Geological Formations, and the Ingleside Sand.
    Texas coastal prairie wetlands are locally abundant and in close 
proximity to other coastal prairie wetlands and function together 
cumulatively. Collectively as a complex, Texas coastal prairie wetlands 
can be geographically and hydrologically connected to each other via 
swales and connected to downstream waters, contributing flow to those 
downstream waters. Cumulatively, these wetlands can control nutrient 
release levels and rates to downstream waters, as they capture, store, 
transform, and pulse releases of nutrients to those waters.
    The agencies conclude that Texas coastal prairie wetlands are 
similarly situated based on their close proximity to each other and the 
tributary network, their hydrologic connections to each other and the 
tributary network, their interaction and formation as a complex of 
wetlands, their density on the landscape, and their similar functions.

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

A. Summary of the Rule

    The rule revises the existing definition of ``waters of the United 
States'' consistent with the CWA, science, the agencies' technical 
expertise and experience, and Supreme Court decisions. The final rule 
establishes categories of waters that are jurisdictional and other 
categories of waters that are excluded, as well as categories of waters 
and wetlands that require a case-specific significant nexus evaluation 
to determine if they are ``waters of the United States'' and covered by 
the CWA. The rule also provides definitions for key terms used in the 
regulation. The final rule retains much of the structure of the 
agencies' longstanding definition of ``waters of the United States,'' 
and many of the existing provisions of that definition where revisions 
are not required in light of Supreme Court decisions or other bases for 
revision. All existing exclusions from the definition of ``waters of 
the United States'' are retained, and several exclusions reflecting 
longstanding agencies' practice are added to the regulation for the 
first time.
    The agencies define ``waters of the United States'' in paragraph 
(a) of the rule for all sections of the CWA to include the traditional 
navigable waters (a)(1), interstate waters (a)(2), the territorial seas 
(a)(3), impoundments of jurisdictional waters (a)(4), covered 
tributaries (a)(5), and covered adjacent waters (a)(6). Waters in these 
categories are jurisdictional ``waters of the United States'' by rule--
no additional analysis is required. This eliminates the need to make a 
case-specific significant nexus determination for covered tributaries 
or covered adjacent waters because the agencies determined that these 
waters have a significant nexus to waters identified in (a)(1) through 
(a)(3) of the rule and thus are ``waters of the United States.'' The 
agencies emphasize that the finding of jurisdiction for these covered 
tributaries and covered adjacent waters was not based on the mere 
connection of a water body to downstream waters, but rather a 
determination that the nexus, alone or in combination with other of 
these covered tributaries or covered adjacent waters in the watershed, 
is significant.
    The agencies exclude specified waters from the definition of 
``waters of the United States'' in paragraph (b) of the rule. The rule 
makes no substantive change to the existing exclusion for waste 
treatment systems designed consistent with the requirements of the CWA 
and makes no change to the existing exclusion for prior converted 
cropland. The rule excludes for the first time certain waters and 
features over which the agencies have generally not asserted CWA 
jurisdiction, as well as groundwater, which the agencies have never 
interpreted to be a ``water of the United States'' under the CWA. 
Codifying these longstanding practices supports the agencies' goals of 
providing greater clarity, certainty, and predictability for the 
regulated public and regulators, and makes rule implementation clear 
and practical.
    This final rule provides clear exclusions for certain types of 
ditches. The final rule also expressly excludes stormwater control 
features created in dry land and certain wastewater recycling 
structures created in dry land. Waters and features that are excluded 
under paragraph (b) of the rule cannot be determined to be 
jurisdictional under any of the categories in the rule under paragraph 
(a).
    In addition to waters that are categorically ``waters of the United 
States'' or categorically excluded under paragraphs (a) and (b), the 
rule identifies certain waters that can be ``waters of the United 
States'' only where a case-specific determination has found a 
significant nexus between the water and traditional navigable waters, 
interstate waters, or the territorial seas. First, paragraph (a)(7) of 
the rule specifies five types of waters (Prairie potholes, Delmarva and 
Carolina bays, pocosins, western vernal pools in California, and Texas 
coastal prairie wetlands) that the agencies have determined to be 
``similarly situated,'' and thus are to be considered in combination in 
a significant nexus analysis. Second, paragraph (a)(8) specifies that 
waters located within the 100-year floodplain of a traditional 
navigable water, interstate water, or the territorial seas, and waters 
located within 4,000 feet from the high tide line or the ordinary high 
water mark of traditional navigable waters, interstate waters, the 
territorial seas, impoundments, or covered tributaries may be found to 
have a significant nexus on a case-specific basis, but the agencies 
have not made a determination that the waters are ``similarly 
situated.'' As a result, a significant nexus analysis for these waters 
will include a case-specific assessment of whether there are any 
similarly situated waters, as well as whether the water, alone or in 
combination with any waters determined to be similarly situated, has a 
significant nexus to a traditional navigable water, interstate water, 
or territorial sea. The rule outlines at (c)(5)(i)-(ix) functions 
relevant to these case-specific significant nexus analyses.
    Paragraph (c) of the rule provides definitions for key terms used 
in the regulation. Some of these are unchanged from the current 
regulations, including the definitions for ``wetlands'' at (c)(4), 
``ordinary high water mark'' at (c)(6) and ``high tide line'' at 
(c)(7), although the latter two are existing, unchanged Corps' 
definitions added to EPA's regulations for the first time. 33 CFR 
328.3(d)-(e). The rule also defines for the first time ``tributary'' 
and ``tributaries'' at (c)(3), ``neighboring'' (an aspect of adjacency) 
at (c)(2), and ``significant nexus'' at (c)(5).
    This rule is effective on August 28, 2015. Under existing Corps' 
regulations and guidance, approved jurisdictional determinations 
generally are valid for five years. The agencies will not reopen 
existing approved jurisdictional determinations unless requested to do 
so by the applicant or, consistent with existing Corps' guidance, 
unless new information warrants revision of the determination before 
the expiration period. Similarly, consistent with existing regulations 
and guidance, approved jurisdictional determinations

[[Page 37074]]

associated with issued permits and authorizations are valid until the 
expiration date of the permit or authorization.
    As a general matter, the agencies' actions are governed by the rule 
in effect at the time the agency issues a jurisdictional determination 
or permit authorization, not by the date of a permit application, 
request for authorization, or request for a jurisdictional 
determination. However, any jurisdictional determinations issued prior 
to the effective date of the rule and jurisdictional determinations 
associated with permit applications deemed by the Corps to have been 
complete on the date this rule is published in the Federal Register, 
including complete pre-construction notifications, will be made 
consistent with the existing rule, unless the applicant requests that 
its approved jurisdictional determination or permit authorization be 
decided after the effective date of the new rule. Reliance on 
preliminary jurisdictional determinations is also not affected by the 
issuance of this rule. All other jurisdictional determinations and 
requests for authorization requiring an approved jurisdictional 
determination issued on or after the effective date of this rule will 
be made consistent with this rule.
    It is important to emphasize that the agencies do not anticipate 
being able to complete new jurisdictional determinations submitted 
after this rule is published before it becomes effective. As a result, 
requesters seeking jurisdictional determinations after the rule is 
published should expect the determination will be made consistent with 
this rule. The agencies recognize there are a number of requests for 
permit applications and requests for jurisdictional determinations 
pending at any time. The agencies expect only a small portion of those 
pending actions will require additional information from or work by the 
requester. As described in the Economic Analysis, the vast majority of 
requests address streams and adjacent wetlands, and the agencies do not 
expect new information or work will be needed to complete those 
requests. If any additional information is needed to assess these 
requests, the agencies will work proactively with permit applicants to 
reduce potential short-term disruptions in the permit process that may 
be associated with the rule.

B. Traditional Navigable Waters

    The existing regulations include within the definition of ``waters 
of the United States'' all waters that are currently used, or were used 
in the past, or may be susceptible to use in interstate or foreign 
commerce, including all waters which are subject to the ebb and flow of 
the tide. See, e.g., 33 CFR 328.3(a)(1); 40 CFR 230.3(s)(1); 40 CFR 
122.2 (``waters of the U.S.''). This paragraph of the regulation 
encompasses those waters that are often referred to as ``traditional 
navigable waters.'' The rule does not make any changes to this 
paragraph of the regulation.
    For purposes of CWA jurisdiction, waters will be considered 
traditional navigable waters, and jurisdictional under (a)(1) of the 
rule, if they:
     Are subject to section 9 or 10 of the Rivers and Harbors 
Appropriations 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
     Are susceptible to being used in the future for commercial 
navigation, including commercial waterborne recreation.
    See Technical Support Document; ``U.S. Army Corps of Engineers 
Jurisdictional Determination Form Instructional Guidebook Appendix D, 
`Traditional Navigable Waters,''' available at: http://www.usace.army.mil/Portals/2/docs/civilworks/regulatory/cwa_guide/app_d_traditional_navigable_waters.pdf.
    The agencies received several comments on the scope of traditional 
navigable waters. Some commenters observed that ``traditional navigable 
waters'' as a jurisdictional category is not based in science. Several 
commenters thought that the final rule should specify considerations to 
be taken into account when determining if a water is susceptible to 
being used in future commercial navigation. The agencies have not 
revised the regulation to address susceptibility, but observe that case 
law has provided a number of considerations and examples that are 
described further in the Technical Support Document and are reflected 
in longstanding agencies' practice.

C. Interstate Waters

    The existing regulations define ``waters of the United States'' to 
include interstate waters, including interstate wetlands. The rule does 
not change that provision of the regulations. Therefore, interstate 
waters are ``waters of the United States'' even if they are not 
navigable for purposes of Federal regulation under (a)(1) and do not 
connect to such waters. Moreover, the rule protects impoundments of 
interstate waters, tributaries to interstate waters, waters adjacent to 
interstate waters, and waters adjacent to covered tributaries of 
interstate waters because they have a significant nexus to interstate 
waters. Protection of these waters is thus critical to protecting 
interstate waters.
    The language of the CWA indicates that Congress intended the term 
``navigable waters'' to include interstate waters without imposing a 
requirement that they be traditional navigable waters themselves or be 
connected to traditional navigable waters. The precursor statutes to 
the CWA subjected interstate waters and their tributaries to Federal 
jurisdiction. The text of the CWA, specifically CWA section 303, which 
establishes ongoing requirements for interstate waters, in conjunction 
with the definition of navigable waters, provides clear indication of 
Congress' intent to protect interstate waters that were previously 
subject to Federal regulation. Other provisions of the statute provide 
additional textual evidence of the scope of the primary jurisdictional 
term of the CWA.
    The agencies also have a longstanding regulatory interpretation 
that interstate waters fall within the scope of CWA jurisdiction. The 
agencies' interpretation was promulgated contemporaneously with the 
passage of the CWA and is consistent with the statutory and legislative 
history of the CWA. Furthermore, the Supreme Court has never addressed 
the CWA's coverage of interstate waters, and it is not reasonable to 
read its decisions in SWANCC and Rapanos to question the jurisdictional 
status of interstate waters or to impose additional jurisdictional 
requirements on interstate waters. The assertion of jurisdiction over 
interstate waters is based on the statute and under predecessor 
statutes where ``interstate waters'' were defined as 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). The agencies 
will continue to implement the provision consistent with the intent of 
Congress. For additional discussion of the agencies' interpretation of 
the CWA with respect to interstate waters, see Appendix B of the 
proposed rule and the Technical Support Document.
    It is reasonable to assert jurisdiction over tributaries, adjacent 
waters, and waters that have a significant nexus to interstate waters 
consistent with the framework set forth in Justice Kennedy's

[[Page 37075]]

opinion in Rapanos for establishing jurisdiction over waters with a 
significant nexus to traditional navigable waters. Waters and wetlands 
with a significant nexus to traditional navigable waters and interstate 
waters have important beneficial effects on those waters, and by 
recognizing that polluting or destroying waters with a significant 
nexus can harm downstream jurisdictional waters. Traditional navigable 
waters and interstate waters cannot be protected without also 
protecting the waters that have a significant nexus to those waters as 
identified in the rule. The rule thus defines ``waters of the United 
States'' to include tributaries to interstate waters, waters adjacent 
to interstate waters, waters adjacent to tributaries of interstate 
waters, and other waters that have a significant nexus to interstate 
waters.
    The agencies received a number of comments on interstate waters. 
Some commenters asserted that interstate waters required a significant 
nexus to a traditional navigable water in order to be jurisdictional 
after Rapanos. The agencies disagree for the reasons described above, 
in Appendix B to the proposed rule, and in the Technical Support 
Document.

D. Territorial Seas

    The CWA and its existing regulations include ``the territorial 
seas'' as a ``water of the United States.'' The rule makes no changes 
to that provision of the regulation other than to change the ordering 
to earlier in the regulation. The CWA defines ``navigable waters'' to 
include ``the territorial seas'' at section 502(7). The CWA goes on to 
define the ``territorial seas'' in section 502(8) as ``the belt of the 
seas measured from the line of ordinary low water along that portion of 
the coast which is in direct contact with the open sea and the line 
marking the seaward limit of inland waters, and extending seaward a 
distance of three miles.'' The territorial seas establish the seaward 
limit of ``waters of the United States.'' The territorial seas are 
clearly covered by the CWA (they are also traditional navigable 
waters), and it is reasonable to protect their covered tributaries and 
covered adjacent waters.
    Although some comments addressed the definition of ``territorial 
seas'' provided in the CWA suggesting that the distance thresholds be 
revised to reflect other resource statutes, the agencies do not have 
authority to revise statutory language.

E. Impoundments

    The existing regulations provide that impoundments of ``waters of 
the United States'' remain ``waters of the United States,'' and the 
rule does not make any changes to the existing regulatory language.
    Impoundments are jurisdictional because an impoundment of a ``water 
of the United States'' remains a ``water of the United States,'' and 
because scientific literature demonstrates that impoundments continue 
to significantly affect the chemical, physical, or biological integrity 
of downstream traditional navigable waters, interstate waters, and the 
territorial seas. See Technical Support Document. 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.''). Similarly, when presented with a tributary to 
the Snake River which flows only about two months per year because of 
an irrigation diversion structure installed upstream, the Ninth Circuit 
noted ``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.'' U.S. v. Moses, 496 
F.3d 984, 988 (9th Cir. 2007), cert. denied, 554 U.S. 918 (2008). As a 
matter of policy and law, impoundments do not de-federalize a water, 
even where there is no longer flow below the impoundment. The agencies 
have analyzed stream networks, above and below impoundments, for 
connection to downstream traditional navigable waters, interstate 
waters, or the territorial seas. Scientific literature, as well as the 
agencies' scientific and technical expertise and experience confirm 
that impoundments have chemical, physical, and biological effects on 
downstream waters. See Technical Support Document.
    The agencies also note that an impoundment of a water that is not a 
``water of the United States'' can become jurisdictional if, for 
example, the impounded waters become navigable-in-fact and covered 
under paragraph (a)(1) of the rule.
    By their nature, impoundments of jurisdictional waters would also 
often meet the definition of ``adjacent waters,'' as they are typically 
bordering or contiguous. Impoundments of ``waters of the United 
States'' are per se jurisdictional under paragraph (a)(4) of the rule 
without the need to determine if they are also adjacent under paragraph 
(a)(6). However, as described in section IV.G below, ``adjacent 
waters,'' as defined, have a significant nexus to traditional navigable 
waters, interstate waters, or the territorial seas, which bolsters the 
agencies' determination that impoundments of ``waters of the United 
States'' remain ``waters of the United States.''
    Impoundments also may be one of the waters through which 
tributaries indirectly contribute flow to a traditional navigable 
water, interstate water, or territorial sea. As a matter of law and 
science, an impoundment does not cut off a connection between upstream 
tributaries and a downstream traditional navigable water, interstate 
water, or territorial sea, so covered tributaries above the impoundment 
are still considered a tributary to downstream traditional navigable 
waters, interstate waters, or the territorial seas even where the flow 
of water might be impeded due to the impoundment. See paragraph (a)(5).
    The agencies received comments on impoundments, which generally 
explored the impacts of impoundments on connectivity to downstream 
waters. For the reasons described above and in the Technical Support 
Document, the agencies concluded that impoundments of ``waters of the 
United States'' remain ``waters of the United States.''

F. Tributaries

    The existing definition of ``waters of the United States'' 
regulates all tributaries without qualification. The final rule 
protects only waters that have a significant effect on the integrity of 
traditional navigable waters, interstate waters, or the territorial 
seas. The rule establishes a definition of ``tributary,'' and provides 
that a water meeting the definition of tributary, unless it is excluded 
under paragraph (b), is a ``water of the United States'' without the 
need for a separate case-specific significant nexus evaluation. As 
explained in Section III above, covered tributaries and the functions 
they provide, alone or in combination with other tributaries in the 
watershed, significantly affect the chemical, physical, and biological 
integrity of traditional navigable waters, interstate waters, or the 
territorial seas. See also Technical Support Document. This section 
describes the provisions of the rule addressing tributaries and changes 
made to the provisions in the proposed rule based on public comments.

[[Page 37076]]

1. What are the provisions in the rule?
    The rule defines ``tributary'' by emphasizing the physical 
characteristics created by sufficient volume, frequency and duration of 
flow, and that the water contributes flow, either directly or through 
another water, to a traditional navigable water, interstate water, or 
the territorial seas. This definition is based on the best available 
science, intent of the CWA, and case law, and is consistent with 
current practice. As mentioned above in Section III, the Science Report 
concludes that ``[t]he scientific literature unequivocally demonstrates 
that streams, individually or cumulatively, exert a strong influence on 
the integrity of downstream waters.'' Science Report at ES-2.
    First, to meet the rule's definition of ``tributary,'' a water must 
flow directly or through another water or waters to a traditional 
navigable water, interstate water, or the territorial seas. Waters 
through which a tributary may contribute flow indirectly include, for 
example, impoundments, wetlands, lakes, and other tributaries. A 
tributary may contribute flow through any number of downstream waters, 
including non-jurisdictional features, such as a ditch excluded under 
paragraph (b) of the rule, and jurisdictional waters that are not 
tributaries, such as an adjacent wetland--but it must be part of a 
tributary system that eventually flows to a traditional navigable 
water, an interstate water, or the territorial seas. This limitation on 
what constitutes a tributary for purposes of this rule is fundamental. 
If a water is not part of the tributary system of a traditional 
navigable water, interstate water, or the territorial seas, it does not 
meet the definition of ``tributary'' and is not jurisdictional under 
this provision of the rule. For example, an intermittent stream that 
exists wholly within one state, is not itself a traditional navigable 
water, and whose flows eventually ends without connecting to a 
traditional navigable water, interstate water, or the territorial seas 
is not a ``water of the United States'' as a ``tributary'' for purposes 
of this rule. To determine whether a water meets this aspect of the 
definition, the connection can be traced using direct observation, U.S. 
Geological Survey (USGS) data, stream datasets such as the National 
Hydrography Dataset, aerial photography or other reliable remote 
sensing information, or other appropriate information.
    Under the rule, flow in the tributary may be perennial, 
intermittent, or ephemeral. The agencies received comments suggesting 
that the final rule provide definitions for the terms ephemeral flow, 
intermittent flow, and perennial flow. The agencies considered the 
request and determined that there was no need to include a definition 
since they are commonly used scientific terms. Longstanding agencies' 
practice considers perennial streams as those with flowing water year-
round during a typical year, with groundwater or contributions of flow 
from higher in the stream or river network as primary sources of water 
for stream flow. Intermittent streams are those that have both 
precipitation and groundwater providing part of the stream's flow, and 
flow continuously only during certain times of the year (e.g., during 
certain seasons such as the rainy season). Ephemeral streams have 
flowing water only in response to precipitation events in a typical 
year, and are always above the water table. Precipitation can include 
rainfall as well as snowmelt. Science shows that tributaries regardless 
of flow duration are very effective at transporting pollutants 
downstream, such as excess nutrients and sediment, which impact the 
integrity and character of traditional navigable waters, interstate 
waters, and the territorial seas. See Technical Support Document.
    Second, the rule requires two physical indicators of flow: There 
must be a bed and banks and an indicator of ordinary high water mark. 
This definition of ``tributary'' includes only those waters the 
agencies have concluded are the type of waters that the CWA was 
intended to protect and which either individually or in combination 
with other covered tributaries in the watershed have a significant 
nexus to a traditional navigable water, interstate water, or the 
territorial seas. Thus, the agencies are not defining ``waters of the 
United States'' to include all streams that might be considered 
``tributaries'' in the general scientific literature. To provide 
additional clarity and for ease of use for the public, the agencies are 
including the Corps' existing definition of ordinary high water mark in 
EPA's regulations as well. Under that existing Corps regulation, 
ordinary high water mark indicators include characteristics such as 
shelving, scour, changes in soil characteristics, and destruction of 
terrestrial vegetation, among others.
    A bed and banks and other indicators of ordinary high water mark 
are physical indicators of water flow and are only created by 
sufficient and regular intervals of flow. These physical indicators can 
be created by perennial, intermittent, and ephemeral flows. See 
Technical Support Document. For purposes of the rule, ``bed and banks'' 
means the substrate and sides of a channel between which flow is 
confined. The banks constitute a break in slope between the edge of the 
bed and the surrounding terrain, and may vary from steep to gradual. 
Existing Corps regulations define ordinary high water mark as the line 
on the shore established by the fluctuations of water and indicated by 
physical characteristics such as a clear, natural line impressed on the 
banks, shelving, changes in the character of soil, destruction of 
terrestrial vegetation, the presence of litter and debris, or other 
appropriate means that consider the characteristics of the surrounding 
areas. 33 CFR 328.3(e). That definition is not changed by the rule and 
is added to EPA's regulations.
    Current Corps regulations and guidance identify bed and banks as 
indicators of the ordinary high water mark. The definition of 
``tributary'' in this rule requires the presence of a bed and banks and 
an additional indicator of ordinary high water mark such as staining, 
debris deposits, or other indicator identified in the rule or agency 
guidance. In many tributaries, the bed is that part of the channel 
below the ordinary high water mark, and the banks often extend above 
the ordinary high water mark. For other tributaries, such as those that 
are incised, changes in vegetation, changes in sediment 
characteristics, staining, or other ordinary high water mark indicators 
may be found within the banks. In concrete-lined channels, the concrete 
acts as the bed and banks and can have other ordinary high water mark 
indicators such as staining and debris deposits. Indicators of an 
ordinary high water mark may vary from region to region across the 
country. See Technical Support Document.
    Other evidence, besides direct field observation, may establish the 
presence of bed and banks and another indicator of ordinary high water 
mark. The agencies currently use many tools in identifying tributaries 
and will continue to rely on their experience and expertise in 
identifying the presence of a bed and banks and ordinary high water 
mark. For example, several reliable, well-established remote sensing 
sources of information or mapping can assist to establish the presence 
of water that contributes flow to a traditional navigable water, 
interstate water, or the territorial seas and provide evidence 
regarding the presence of a bed and banks and another indicator of 
ordinary high water mark. Among the types of remote sensing or mapping 
information that can assist in establishing the presence of water are 
USGS topographic

[[Page 37077]]

data, the USGS National Hydrography Dataset (NHD), Natural Resources 
Conservation Service (NRCS) Soil Surveys, and State or local stream 
maps, as well as the analysis of aerial photographs, and light 
detection and ranging (also known as LIDAR) data, and desktop tools 
that provide for the hydrologic estimation of a discharge sufficient to 
create an ordinary high water mark, such as a regional regression 
analysis or hydrologic modeling. These sources of information can 
sometimes be used independently to infer the presence of a bed and 
banks and another indicator of ordinary high water mark, or where they 
correlate, can be used to reasonably conclude the presence of a bed and 
banks and ordinary high water mark.
    Both the USGS topographic data and the NHD data assist to delineate 
tributaries to traditional navigable waters, interstate waters, or the 
territorial seas. Where one or both of these sources have indicated a 
``blue line stream,'' there is an indication that the tributary could 
exhibit a bed and banks and another indicator of ordinary high water 
mark. Where this information is combined with stream order,\11\ more 
certainty can result. For example, a water that is a second-order 
stream will be more likely to exhibit a bed and banks and another 
indicator of ordinary high water mark as compared to a first-order 
stream. This information will vary in validity in different parts of 
the country, so care will be taken to evaluate additional information 
prior to reasonably concluding a bed and banks or other indicators of 
ordinary high water mark are associated with the stream. This will be 
particularly true for first-order streams and for many streams in the 
arid portions of the country. Supporting information that can be used 
to conclude the presence of a bed and banks and another indicator of 
ordinary high water mark would be the presence of USGS stream data on 
the NRCS county Soil Survey or local stream maps which are mapped 
independently of the USGS, aerial photography interpretation, or 
digital terrain depictions created from LIDAR. See Technical Support 
Document.
---------------------------------------------------------------------------

    \11\ Stream order is a method for stream classification based on 
relative position within a river network, when streams lacking 
upstream tributaries (i.e., headwater streams) are first-order 
streams and the junction of two streams of the same order results in 
an increase in stream order (i.e., two first-order streams join to 
form a second-order stream, and so on). When streams of different 
orders join, the order of the larger stream is retained. See Science 
Report and Technical Support Document.
---------------------------------------------------------------------------

    Tributaries are observable in aerial photography by their 
topographic expression, characteristic linear and curvilinear patterns, 
dark photographic tones, and the presence and pattern of riparian 
vegetation. The characteristic linear and curvilinear patterns and dark 
photographic tones observed on aerial photography can be caused by 
shadow cast from the banks of an incised stream or from water in the 
stream channel itself. In some cases stream channel morphology is 
visible, providing evidence of scour, materials sorting, and 
deposition, all characteristics of an ordinary high water mark. Visible 
persistent water (e.g., multiple dates of aerial photography showing 
visible water) provides strong evidence of the sufficient frequency and 
duration of surface flow to create a bed and banks and other indicators 
of ordinary high water mark. Visible indicators of running water such 
as rapids, riffles, and pools all indicate the presence of a bed and 
banks and other indicators of ordinary high water mark. Other physical 
characteristics of an ordinary high water mark that may be visible on 
aerial photography include the destruction of terrestrial vegetation 
and the absence of vegetation in a channel. These indicators gleaned 
from aerial photography interpretation can be correlated with the 
presence of USGS streams data in reasonably concluding that a bed and 
banks and another indicator of ordinary high water mark are present. 
See Technical Support Document.
    Additional desktop tools can assist in the identification of bed 
and banks and other indicators of ordinary high water mark. For 
instance, field staff use other methods for estimating ordinary high 
water mark, including, but not limited to, lake and stream gage data, 
flood predictions, historic records of water flow, and statistical 
evidence. Some desktop tools, such as a regional regression analysis 
and the Hydrologic Modeling System (HEC-HMS), provide for the 
hydrologic estimation of stream discharge sufficient to create an 
ordinary high water mark in tributaries under regional conditions. Such 
desktop tools are particularly useful for identifying presence of bed 
and banks and another indicator of ordinary high water mark when 
supported by additional remote sensing tools that indicate the presence 
of such physical features.
    LIDAR is a powerful tool to analyze the characteristics of the land 
surface, including tributary identification and characterization. LIDAR 
data are becoming more and more widespread for engineering and land use 
planning purposes. Where LIDAR data have been processed to create a 
bare earth model, detailed depictions of the land surface are 
available. Bare earth models reveal subtle elevation changes and can 
clearly show a tributary's bed and banks and channel morphology. In 
many cases LIDAR can help delineate tributaries that would exhibit a 
bed and banks and another indicator of an ordinary high water mark in 
greater detail than aerial photography interpretation alone can. 
Visible linear and curvilinear incisions on a bare earth model are 
strong evidence that a tributary with a bed and banks and another 
indicator of an ordinary high water mark is present. LIDAR-indicated 
tributaries can be correlated with aerial photography interpretation 
and USGS stream data, to reasonably conclude the presence of a bed and 
banks and another indicator of an ordinary high water mark in the 
absence of a field visit. See Technical Support Document. The agencies 
have been using such remote sensing and desktop tools to delineate 
tributaries for many years where data from the field are unavailable or 
a field visit is not possible.
    In addition, such desktop tools are critical in circumstances where 
physical characteristics of bed and banks and another indicator of 
ordinary high water mark are absent in the field, often due to 
unpermitted alteration of streams. In such cases where physical 
characteristics of bed and banks and another indicator of ordinary high 
water mark no longer exist, they may be determined by using other 
appropriate means that consider the characteristics of the surrounding 
areas. Such reliable methods that can indicate prior existence of bed 
and banks and other indicators of ordinary high water mark include, but 
are not limited to, lake and stream gage data, elevation data, spillway 
height, historic water flow records, flood predictions, statistical 
evidence, the use of reference conditions, or through the remote 
sensing and desktop tools described above.
    The upper limit of the tributary is the point where a bed and banks 
and another indicator of ordinary high water mark cease to be 
identifiable. The ordinary high water mark establishes the lateral 
limits of a water, and its absence generally determines when a 
tributary's channel or bed and banks has ended, representing the upper 
limit of the tributary. However, a natural or constructed break in bed 
and banks or other indicator of ordinary high water mark does not 
constitute the upper limit of a tributary where bed and banks or other 
indicator ordinary high water mark can be found farther upstream. Note 
that waters, including wetlands, which are adjacent to a tributary at 
the

[[Page 37078]]

upper limit of the channel are jurisdictional as ``adjacent waters.''
    The definition of ``tributary'' includes tributaries that flow 
directly or indirectly through impoundments that are jurisdictional 
under paragraph (a)(4) of the rule. Tributaries to impoundments of 
``waters of the United States'' are jurisdictional for the same reasons 
the impoundments themselves are jurisdictional. As discussed in section 
IV. E., under case law, an impoundment of a ``water of the United 
States'' remains a ``water of the United States,'' and scientific 
literature demonstrates that impoundments continue to significantly 
affect the chemical, physical, or biological integrity of downstream 
waters traditional navigable waters, interstate waters, and the 
territorial seas. Therefore, tributaries to such impoundments continue 
to have a significant nexus, alone or in combination with other covered 
tributaries in the watershed, to the downstream traditional navigable 
water, interstate water, or the territorial seas.
    Waters that meet the rule definition of tributary remain 
tributaries even if there is a manmade or natural break at some point 
along the connection to the traditional navigable water, interstate 
water, or the territorial seas. In many tributaries, there are often 
natural or constructed breaks in the presence of a bed and banks or 
ordinary high water mark while hydrologic connectivity remains. For 
example, in some regions of the country where there is a very low 
gradient, the banks of a tributary may be very low or may even 
disappear at times. Many tributaries lose their ordinary high water 
mark when adjacent wetlands are contiguous with the stream channel. The 
definition of ``tributary'' addresses these circumstances and states 
that waters that meet the definition of tributary remain tributaries 
even if such breaks occur, so long as bed and banks and an ordinary 
high water mark are present upstream of the break. Under the rule, when 
a covered tributary flows through a wetland into another tributary 
(sometimes called a ``run-of-stream'' wetland), the covered tributary 
remains jurisdictional even though it lost its ordinary high water mark 
through the wetland. By looking to the presence of a bed and banks and 
an ordinary high water mark upstream, the rule ensures that a mere 
break in the ordinary high water mark does not render tributaries with 
a significant nexus to downstream waters not jurisdictional. Other 
breaks that do not sever jurisdiction include constructed breaks such 
as bridges, culverts, pipes, dams, or waste treatment systems, or 
natural breaks such as debris piles, boulder fields, or a stream that 
flows underground so long as a bed and banks and an ordinary high water 
mark can be identified upstream of the break. Site specific conditions 
will continue to determine the distance up valley that needs to be 
evaluated to see if the break in bed and banks and ordinary high water 
mark is temporary or the start of the stream system.
    The rule also clarifies that a water meets the definition of 
tributary if the water contributes flow through an excluded feature 
such as a ditch with ephemeral flow. While the water above and below 
the excluded feature is jurisdictional if it meets the definition of 
tributary, the excluded feature does not become jurisdictional. A water 
also continues to meet the definition of tributary if at some point the 
water contributes flow through a jurisdictional water that is not a 
tributary, such as an adjacent wetland or impoundment.
    The agencies' longstanding interpretation of the CWA has included 
tributaries that are natural, modified, or constructed waters. While 
this rule at paragraph (b) excludes specific types of constructed 
waters from jurisdiction, it continues to interpret constructed 
tributaries as jurisdictional unless expressly excluded in paragraph 
(b). Natural, modified, and constructed 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 discharge of a 
pollutant into a tributary generally has the same effect downstream 
whether the tributary waterway is natural, modified, or constructed. 
See discussion in section III.C. above and the Technical Support 
Document. 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 modified or constructed. For example, tributaries that 
have been channelized in concrete or otherwise have been modified may 
still meet the definition of tributaries under the rule so long as they 
have bed and banks and an ordinary high water mark, contribute flow to 
a traditional navigable water, interstate water, or the territorial 
seas, and are not excluded under paragraph (b). The important 
consideration for a modified or constructed water is whether it meets 
the definition of ``tributary'' and is not excluded under paragraph 
(b).
    Ditches are one important example of constructed features that in 
many instances can meet the definition of tributary. Ditches are 
jurisdictional under the rule only if they both meet the definition of 
``tributary'' and are not excluded under paragraph (b)(3) in the rule. 
Not all ditches meet the definition of a tributary, and others--as 
discussed in Section I--are expressly excluded from jurisdiction.
    Ditches protected by the rule must meet the definition of 
tributary, having a bed and banks and ordinary high water mark, and 
contributing flow directly or indirectly through another water to a 
traditional navigable water, interstate water, or the territorial seas. 
Jurisdictional ditches include ditches such as the following:
     Ditches with perennial flow,
     Ditches with intermittent flow that are a relocated 
tributary, or are excavated in a tributary, or drain wetlands,
     Ditches, regardless of flow, that are excavated in or 
relocate a tributary.
    The definition of tributary includes natural, undisturbed waters 
and those that have been man-altered or constructed, but which science 
shows function as a tributary. In addition, alteration or modification 
of natural streams and rivers for purposes such as flood control, 
erosion control, and other reasons does not convert the tributary to a 
ditch. A stream or river that has been channelized or straightened 
because its natural sinuosity has been altered, cutting off the 
meanders, is not a ditch. A stream that has banks stabilized through 
use of concrete or rip-rap (e.g., rocks or stones) is not a ditch. The 
Los Angeles River, for example, is a ``water of the United States'' 
(and, indeed, a traditional navigable water) and remains a ``water of 
the United States'' and is not excluded under paragraph (b)(3) even 
where it has been ditched, channelized, or concreted.
    A ditch that relocates a stream is not an excluded ditch under 
paragraph (b)(3), and a stream is relocated either when at least a 
portion of its original channel has been physically moved, or when the 
majority of its flow has been redirected. A ditch that is a relocated 
stream is distinguishable from a ditch that withdraws water from a 
stream without changing the stream's aquatic character. The latter type 
of ditch is excluded from jurisdiction where it meets the listed 
characteristics of excluded ditches under paragraph (b)(3). Agency 
staff can determine historical presence of tributaries using a variety 
of resources, such as historical maps, historic aerial photographs, 
local surface water management plans, street

[[Page 37079]]

maintenance data, wetlands and conservation programs and plans, as well 
as functional assessments and monitoring efforts. A ditch with 
intermittent flow that drains a wetland and otherwise meets the 
definition of ``tributary'' is a ``tributary'' and is not excluded 
under paragraph (b)(3). See IV.I. below.
    Evidence, such as current or historic photographs, prior 
delineations, or USGS, state and local topographic maps, may be used to 
determine whether a ditch is an excluded ditch. Site characteristics 
may also be present to inform the determination of whether the water 
body is a ditch, such as shape, sinuosity, flow indications, etc., as 
ditches are often created in a linear fashion with little sinuosity and 
may or may not connect to another ``water of the United States.''
2. What changes did the Agencies make from the proposed rule based on 
public comments?
    The rule's definition of ``tributary'' retains many elements from 
the proposed rule, but reflects public comments in several important 
ways. In particular, the rule emphasizes flow. The rule defines 
``tributary'' by emphasizing physical characteristics created by water 
flow and requiring that the water contributes flow, either directly or 
through another water, to a traditional navigable water, interstate 
water, or the territorial seas. The rule also is clearer regarding the 
jurisdictional status of certain ditches, and clarifies that wetlands 
and waters such as ponds and lakes that contribute flow to a 
traditional navigable water, interstate water, or the territorial seas 
but typically lack a bed and banks and ordinary high water mark are 
considered ``adjacent'' but not a ``tributary.''
    A number of commenters suggested that the agencies should exclude 
ephemeral streams from the definition of tributary, expressing concern 
that ephemeral waters that flow very rarely would be considered a 
jurisdictional tributary. The rule definition of ``tributary'' requires 
that flow must be of sufficient volume, frequency, and duration to 
create the physical characteristics of bed and banks and an ordinary 
high water mark. If a water lacks sufficient flow to create such 
characteristics, it is not considered a ``tributary'' under this rule. 
While some commenters expressed concern that a feature that flowed very 
rarely could meet the proposed definition of ``tributary,'' it is the 
agencies' judgment that such a feature is not a tributary under the 
rule because it would not form the physical indicators required under 
the definitions of ``ordinary high water mark'' and ``tributary.''
    The rule includes ephemeral streams that meet the definition of 
tributary as ``waters of the United States'' because the agencies 
determined that such streams provide important functions for downstream 
waters, and in combination with other covered tributaries in a 
watershed significantly affect the chemical, physical, and biological 
integrity of traditional navigable waters, interstate waters, and the 
territorial seas. As noted by the SAB, and consistent with the 
scientific literature, tributaries as a group exert strong influence on 
the chemical, physical, and biological integrity of downstream waters, 
even though the degree of connectivity is a function of variation in 
the frequency, duration, magnitude, predictability, and consequences of 
chemical, physical, and biological processes. See, e.g., SAB 2014b. 
These significant effects on traditional navigable waters, interstate 
waters, and the territorial seas occur even when the tributary is 
small, intermittent, or ephemeral.
    In addition, the Science Report concludes that, ``[a]lthough less 
abundant, the available evidence for connectivity and downstream 
effects of ephemeral streams was strong and compelling, particularly in 
context with the large body of evidence supporting the physical 
connectivity and cumulative effects of channelized flows that form and 
maintain stream networks.'' Science Report at 6-13. For example, 
ephemeral headwater streams shape river channels in traditional 
navigable or interstate waters by accumulating and gradually or 
episodically releasing stored materials such as sediment and large 
woody debris. These materials help structure traditional navigable and 
interstate river channels by slowing the flow of water through channels 
and providing substrate and habitat for aquatic organisms.
    Moreover, the agencies have historically considered ephemeral 
tributaries to be ``waters of the United States.'' For example, for 
many years EPA has reviewed and approved state water quality standards 
for ephemeral waters under CWA section 303(c), several Corps' 
Nationwide Permits under CWA section 404 address discharges of dredged 
or fill material into ephemeral waters, and the agencies' definition of 
``waters of the United States'' prior to this rule included all 
tributaries without reference to flow regime.
    Numerous commenters asked that the final rule define ``bed and 
banks,'' which are physical characteristics called for under the 
definition of tributary. Such commenters emphasized the importance of a 
definition of ``bed and banks,'' and some suggested definitional 
language. To increase clarity, the preamble in IV.F.1. above includes a 
definition of bed and banks adapted largely from longstanding agencies' 
practice as well as comments. Several commenters suggested that the 
rule should add a definition of ``ordinary high water mark.'' In 
response and to increase clarity, the rule adds the Corps' existing 
regulatory ordinary high water mark definition to EPA's regulations. 
Corps technical manuals are available to help identify ordinary high 
water mark, referenced above. Several commenters suggested that the 
agencies not require a tributary to have both bed and banks and 
ordinary high water mark, because bed and banks are themselves an 
indicator of ordinary high water mark, and because ordinary high water 
mark alone is an appropriate criterion for many streams in the arid 
west where the characteristic of bed and banks is less common. The 
agencies based their significant nexus determination for the covered 
tributaries in part on the amount of flow indicated where a tributary 
has both a bed banks and another indicator of ordinary high water mark, 
so the rule continues to require both physical indicators with the 
preamble at IV.F.1. above clarifying the means to conclude that those 
indicators exist.
    Several commenters suggested that the rule exclude all constructed 
waters from the definition of ``waters of the United States.'' While 
the rule does exclude several types of constructed waters from 
jurisdiction, it continues to consider constructed tributaries as 
jurisdictional unless expressly excluded in paragraph (b) for the 
reasons described in section IV.I. and the Technical Support Document.
    Many comments recommended that wetlands, ponds, and lakes that 
contribute flow to a traditional navigable water, interstate water, or 
the territorial seas but lack a bed and banks and ordinary high water 
mark not be considered as tributaries, because of the importance of 
those physical characteristics to the definition. Wetlands typically 
lack bed and banks and ordinary high water mark, while lakes and ponds 
typically have an ordinary high water mark and a bed but may lack 
banks. The proposed rule expressly sought comment on whether such 
waters should be considered as tributaries or as ``adjacent waters,'' 
recognizing that it might add an element of uncertainty to the 
definition of

[[Page 37080]]

``tributary'' to include waters that lacked the physical features 
called for in the definition. In addition, the SAB commented that 
tributaries are not typically defined to include lentic systems (still 
waters), and suggested that the agencies reconsider including ponds, 
lakes, and wetlands as covered adjacent waters instead of tributaries. 
SAB 2014b at 2. In response, the rule does not consider these waters to 
be tributaries, but defines covered adjacent waters to include 
wetlands, lakes, and ponds that connect segments of tributaries or are 
at the head of the tributary system. See section G for further 
discussion.

G. Adjacent Waters

    Section III above explains the basis for the agencies' conclusion 
that covered adjacent waters have a significant nexus with 
traditionally navigable waters, interstate waters, or the territorial 
seas. The adjacency provision is based on the best available science, 
intent of the CWA, and case law, and is consistent with the experience 
of the agencies in making case-specific significant nexus 
determinations. As discussed above in Section III, the SAB concludes, 
``[t]he available science supports [the agencies'] proposal to include 
adjacent waters and wetlands as waters of the United States.'' SAB 
2014b at 2. This section describes the provisions of the rule governing 
adjacent waters, changes made to the adjacent waters provision based on 
comments on the proposed rule, and, finally, how science and the law 
support the agencies' conclusions in the final rule.
1. What are the provisions of the rule?
    Under the rule, ``adjacent'' means bordering, contiguous, or 
neighboring, including waters separated from other ``waters of the 
United States'' by constructed dikes or barriers, natural river berms, 
beach dunes, and the like. Waters adjacent to a traditional navigable 
water, interstate water, territorial sea, impoundment, or tributary, 
are ``waters of the United States.'' For purposes of adjacency, an 
adjacent water includes wetlands within or abutting its ordinary high 
water mark. Adjacency is not limited to waters located laterally to a 
traditional navigable water, interstate water, the territorial seas, an 
impoundment, or a tributary. Therefore, waters that connect segments of 
a traditional navigable water, interstate water, the territorial seas, 
an impoundment, or a tributary or are located at the head of a 
traditional navigable water, interstate water, the territorial seas, an 
impoundment, or a tributary may be determined to be bordering, 
contiguous, or neighboring, and thus adjacent. ``Adjacent waters'' 
include wetlands, ponds, lakes, oxbows, impoundments, and similar water 
features. ``Adjacent waters'' do not include any water excluded under 
paragraph (b) of the rule. Note also that a water that does not meet 
the definition of ``adjacent waters'' may be determined to be a ``water 
of the United States'' on a case-specific basis under paragraph (a)(8) 
of the rule.
    Within the definition of ``adjacent,'' the terms bordering and 
contiguous are well understood, and for continuity and clarity the 
agencies continue to interpret and implement those terms consistent 
with the current policy and practice. Waters separated by a berm or 
other similar feature remain ``adjacent'' under the definition.
    Some waters included under the definition of ``tributary'' in the 
proposed rule, after consideration of public comment, are ``adjacent'' 
in the final rule. Specifically, waters that connect segments of, or 
are at the head of, a traditional navigable water, interstate water, 
the territorial seas, an impoundment, or a tributary are adjacent to 
that water. For example, a pond that is the source water to a tributary 
and borders the tributary at its uppermost reach is jurisdictional as 
an adjacent water. Further, the rule states that an adjacent water 
includes wetlands within or abutting its ordinary high water mark. This 
language is designed to ensure that if there is a fringe wetland 
abutting that pond that is the source water to a tributary, that 
wetland is considered part of the pond under the rule and such pond as 
a whole, including any abutting wetlands, is jurisdictional as an 
adjacent water.
    For purposes of adjacency, including all three provisions of the 
definition of ``neighboring,'' the entire water is adjacent if any part 
of the water is bordering, contiguous or neighboring. Therefore, the 
entire wetland is ``adjacent'' if any part of it is within the distance 
thresholds established in the definition of ``neighboring.'' For 
example, if a tributary has a 1,000 foot wide 100-year floodplain, then 
a water that is located within 1,000 feet of the ordinary high water 
mark of a covered tributary and extends to 2,000 feet is jurisdictional 
in its entirety as ``neighboring.'' In addition, for purposes of 
determining whether a water is ``adjacent'' artificial features (such 
as roads) do not divide a water; rather, the water is treated as one 
entire water.
    The definition of ``adjacent'' in the rule does not include those 
waters in which established, normal farming, silviculture, and ranching 
activities occur. Wetlands and farm ponds in which normal farming 
activities occur, as those terms are used in section 404(f) of the 
Clean Water Act and its implementing regulations, are not 
jurisdictional under the Act as an ``adjacent'' water. Waters in which 
normal farming, ranching, and silviculture activities occur instead 
will continue to be subject to case-specific review, as they are today. 
These waters may be determined to have a significant nexus on a case-
specific basis under paragraph (a)(7) or (a)(8). Recognizing the vital 
role of farmers in providing the nation with food, fiber, and fuel, the 
Clean Water Act in Section 404(f) exempts many normal farming 
activities such as seeding, harvesting, cultivating, planting, soil and 
water conservation practices, and other activities from the Section 404 
permitting requirement. ``Normal'' farming, ranching, and silviculture 
is clarified in the agencies' implementing regulations to mean 
established and ongoing activities to distinguish from activities 
needed to convert an area to farming, silviculture, or ranching and 
activities that convert a water to a non-water. 40 CFR 232.3(c)(1). The 
rule reflects this framework by clarifying the waters in which the 
activities Congress exempted under Section 404(f) occur are not 
jurisdictional as ``adjacent.'' It is important to recognize that 
``tributaries,'' including those ditches that meet the tributary 
definition, are not ``adjacent'' waters and are jurisdictional by rule.
    This provision interprets the intent of Congress and reflects the 
intent of the agencies to minimize potential regulatory burdens on the 
nation's agriculture community, and recognizes the work of farmers to 
protect and conserve natural resources and water quality on 
agricultural lands. While waters in which normal farming, silviculture, 
or ranching practices occur may be determined to significantly affect 
the chemical, physical, or biological integrity of downstream navigable 
waters, the agencies believe that such determination should be made 
based on a case-specific basis instead of by rule. The agencies also 
recognize that waters in which normal farming, silviculture, or 
ranching practices occur are often associated with modifications and 
alterations including drainage, changes to vegetation, and other 
disturbances the agencies believe should be specifically considered in 
making a significant nexus determination.
    The rule establishes a definition of ``neighboring'' for purposes 
of determining adjacency. In the rule, the

[[Page 37081]]

agencies identify three circumstances under which waters would be 
``neighboring'' and therefore ``waters of the United States.''
    First, the term ``neighboring'' includes all waters located in 
whole or in part within 100 feet of the ordinary high water mark of a 
traditional navigable water, interstate water, the territorial seas, an 
impoundment, or a covered tributary.
    Second, the term ``neighboring'' includes all waters within the 
100-year floodplain of a traditional navigable water, interstate water, 
the territorial seas, an impoundment, or a covered tributary that is 
located in whole or in part within 1,500 feet of the ordinary high 
water mark of that jurisdictional water. In this rule, the agencies 
interpret ``100-year floodplain'' to mean ``the area that will be 
inundated by the flood event having a one percent chance of being 
equaled or exceeded in any given year.'' This is consistent with the 
Federal Emergency Management Agency's (FEMA) definition of ``100-year 
flood.'' If the 100-year floodplain is greater than 1,500 feet from the 
ordinary high water mark, only those waters that are located in whole 
or in part within 1,500 feet of the ordinary high water mark are 
``neighboring.'' In addition, if the 100-year floodplain is less than 
1,500 feet from the ordinary high water mark, only those waters located 
in whole or in part within the floodplain are ``neighboring'' under 
this provision.
    Third, the rule defines ``neighboring'' to include all waters 
located in whole or in part within 1,500 feet of the high tide line of 
a traditional navigable water or the territorial seas, and all waters 
located within 1,500 feet of the ordinary high water mark of the Great 
Lakes. This provision defines waters that begin within 1,500 feet of a 
tidally-influence traditional navigable water or the territorial seas 
and waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes as ``waters of the United States.'' To provide clarity for 
this aspect of the definition, the agencies incorporated the Corps' 
existing definition of high tide line into EPA's regulations at 
paragraph (c)(7) in the rule.
    As noted above, the rule provides that with respect to the 
boundaries for covered adjacent waters the entire water is 
jurisdictional as long as the water is at least partially located 
within the distance threshold, and the agencies interpret the rule to 
apply to any single water or wetland that may straddle a distance 
threshold. Low-centered polygonal tundra and patterned ground bogs 
(also called strangmoor, string bogs, or patterned ground fens) are 
considered a single water for purposes of the rule because their small, 
intermingled wetland and non-wetland components are physically and 
functionally integrated. These areas often have complex micro-
topography with repeated small changes in elevation occurring over 
short distances. Science demonstrates that these wetlands function as a 
single wetland matrix having clearly hydrophytic vegetation, hydric 
soils, and wetland hydrology. As a result, the agencies will continue 
to evaluate these wetlands as a single water under the rule. Where any 
portion of these wetland types is bordering, contiguous or neighboring, 
the entire wetland is a ``water of the United States.'' Similarly, for 
purposes of a case-specific determination under paragraph (a)(8), 
wetlands of these types constitute a single water when making a 
significant nexus determination. Other wetlands may also have 
intermingled wetland and non-wetland components that are so physically 
and functionally integrated they can be considered a single water for 
purposes of the rule. Groups of wetlands that are simply part of a 
complex of wetlands would not be considered a single water for purposes 
of the rule.
    The final rule also makes some ministerial changes to the 
definition of ``adjacent.'' The existing regulation defined 
``adjacent'' to mean ``bordering, contiguous, or neighboring,'' and had 
a second sentence that clarified that wetlands separated by berms and 
the like remain adjacent wetlands. The final rule combines those 
sentences without changing the scope of adjacency.
    When determining the jurisdictional boundaries under the CWA for 
``adjacent waters,'' the agencies will rely on published FEMA Flood 
Zone Maps to identify the location and extent of the 100-year 
floodplain. https://msc.fema.gov/portal. These maps are publicly 
available and provide a readily accessible and transparent tool for the 
public and agencies to use in locating the 100-year floodplain. It is 
important to recognize, however, that much of the United States has not 
been mapped by FEMA and, in some cases, a particular map may be out of 
date and may not accurately represent existing circumstances on the 
ground. The agencies will determine if a particular map is no longer 
accurate based on factors, such as streams or rivers moving out of 
their channels with associated changes in the location of the 
floodplain. In the absence of applicable FEMA maps, or in circumstances 
where an existing FEMA map is deemed by the agencies to be out of date, 
the agencies will rely on other available tools to identify the 100-
year floodplain, including other Federal, State, or local floodplain 
maps, Natural Resources Conservation Service (NRCS) Soil Surveys 
(Flooding Frequency Classes), tidal gage data, and site-specific 
modeling (e.g., Hydrologic Engineering Centers River System Analysis 
System or HEC-RAS). http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm and HEC-RAS and http://www.hec.usace.army.mil/software/hec-ras/. Additional supporting information can include historical 
evidence, such as photographs, prior delineations, topographic maps, 
and existing site characteristics. Because identifying the 100-year 
floodplain is an important aspect of establishing jurisdiction under 
the rule and the reliable and appropriate tools for identifying the 
100-year floodplain may vary, the agencies will coordinate with other 
federal and state agencies to develop additional information for EPA 
and Corps field staff to further improve tools for identifying the 100-
year floodplain in a consistent, predictable, and scientifically valid 
manner.
    When determining the outer distance threshold for an ``adjacent 
water'' the line is drawn perpendicular to the ordinary high water mark 
or high tide line of the traditional navigable water, interstate water, 
the territorial seas, impoundment, or covered tributary and extended 
landward from that point. If there are breaks in the ordinary high 
water mark, the line should be extrapolated from the point where the 
ordinary high water mark is observed on the downstream side to the 
point where the ordinary high water mark is lost on the upstream side. 
Therefore, waters may meet the definition of neighboring even where, 
for example, a tributary temporarily flows underground.
    The agencies emphasize that they fully support efforts by States 
and tribes to protect under their own laws any additional waters, 
including locally special waters that may not be within the Federal 
protections of the CWA as the agencies have interpreted its scope in 
this rule. In promulgating the adjacent water boundaries, the agencies 
have balanced protection and clarity, scientific uncertainties and 
regulatory experience, and established boundaries that are, in their 
judgment, reasonable and consistent with the statute and its goals and 
objectives.
    If waters identified in this section are determined to be adjacent, 
no case-specific significant nexus evaluation is required.

[[Page 37082]]

2. What changes did the agencies make from the proposed rule based on 
public comments?
    In the proposal, the agencies sought comment on a number of ways to 
address and clarify jurisdiction over ``adjacent waters,'' including 
establishing a floodplain interval and providing clarity on reasonable 
proximity as an important aspect of adjacency. In light of the 
comments, the science, the agencies' experience, and the Supreme 
Court's consistent recognition of the agencies' discretion to interpret 
the bounds of CWA jurisdiction, the agencies have made some revisions 
in the final rule designed to more clearly establish boundaries on the 
scope of ``adjacent waters.''
    Under the proposal and the final rule, ``adjacent waters'' are 
jurisdictional based on the conclusion that they have a significant 
nexus to traditional navigable waters, interstate waters, or the 
territorial seas, and there is no need for additional analysis. Some 
commenters wanted a case-specific analysis for all ``adjacent waters'' 
as they believed that the waters would not individually have a 
significant nexus to an adjacent ``water of the United States,'' while 
others noted that their functional relationship to the downstream 
traditional navigable waters, interstate waters, or the territorial 
seas warranted the conclusion that they were all jurisdictional. Based 
on a review of the science, the agencies' expertise and experience, and 
the law, the agencies determined that ``adjacent waters,'' as defined, 
alone or in combination with other covered ``adjacent waters'' in a 
watershed have a significant nexus to a traditional navigable water, 
interstate water or the territorial seas and therefore are ``waters of 
the United States'' without the need for any additional analysis. 
However, the rule also provides for case-specific analysis of some 
waters that do not meet the definition of ``neighboring'' established 
by the rule. See section IV.H.
    The proposal included wetlands, ponds, lakes, and impoundments that 
contribute flow, directly or indirectly, to the downstream traditional 
navigable waters, interstate waters, or the territorial seas in the 
definition of ``tributary.'' Some commenters expressed concern that 
since such waters generally do not have both an ordinary high water 
mark and a bed and banks, the definition of tributary was contradictory 
and confusing. The agencies sought comment on whether to treat these 
waters as ``adjacent waters'' instead of tributaries, since they not 
only contribute flow, but they also border or are contiguous to the 
waters to which they contribute flow. The SAB in particular commented 
that the agencies ``may want to consider whether flow-through lentic 
systems should be included as ``adjacent waters'' and wetlands, rather 
than as tributaries.'' SAB 2014b at 2. In light of the comments and to 
provide additional clarity, the agencies revised the definitions of 
``adjacent'' and ``tributary'' to include these waters as ``adjacent.''
    Under the existing rule, there is no definition for the term 
``neighboring,'' and the public commented that not having a definition 
created a lack of clarity and inconsistent field practices across the 
nation. In the proposal, ``neighboring'' was defined to include waters 
located within the riparian area or floodplain of a traditional 
navigable water, interstate water, territorial sea, impoundment, or 
tributary; waters with a shallow subsurface hydrologic connection to a 
jurisdictional water; and waters with a confined surface hydrologic 
connection to a jurisdictional water. Although the definitions were 
scientifically-based for the terms ``riparian area'' and ``floodplain'' 
to define the lateral reach of the term ``neighboring,'' some 
commenters indicated that the proposed definitions to clarify 
neighboring were not clear. Those commenters requested that a specific 
floodplain interval or other limitation should be established to more 
clearly identify the outer limit of neighboring. Some commenters stated 
that the proposed definition of ``neighboring'' was unclear, while 
other commenters found the definition helped clarify CWA jurisdiction 
and were supportive of including a broad definition, based on 
ecological interconnectedness.
    Some commenters stated that the proposed definitions of ``riparian 
area'' and ``floodplain'' were vague or ambiguous, broad or effectively 
limitless, beyond the agencies' authority or difficult or impossible to 
implement in the field. Other commenters were supportive of using the 
riparian area as a basis for adjacency. Some commenters asked why the 
agencies were proposing a new definition of ``floodplain'' that was 
inconsistent with the definition used by other Federal agencies like 
NRCS or FEMA. Some commenters suggested that if the agencies use 
floodplains as a means to define ``neighboring,'' it should be limited 
to the area inundated by the 2-year, 5-year, 10-year, or 20-year flood, 
while other commenters supported the use of the 100-year floodplain as 
a component of ``neighboring.'' Some commenters supported including all 
wetlands and other waters in the 100-year floodplain as categorically 
jurisdictional. Other commenters requested that floodplain size be 
based on tributary size, while others suggested that it should be based 
on soil and geologic features, and some suggested the use of the FEMA 
flood zone maps. Some commenters stated that ``reasonable proximity'' 
was neither defined nor clarified adjacency, noting that adjacency 
should not apply to waters separated from a ``water of the United 
States'' by great distances.
    In response to comments and to provide greater clarity and 
consistency, in the rule the agencies establish a definition of 
neighboring which provides additional specificity requested by some 
commenters, including establishing a floodplain interval and providing 
specific boundaries from traditional navigable waters, interstate 
waters, the territorial seas, impoundments, and tributaries. In the 
proposal, the agencies requested comment on whether the rule should 
provide greater specificity with regard to how the agencies will 
determine if a water is located in the floodplain of a jurisdictional 
water. 79 FR 22209. As recommended by the public and based on science, 
the agencies' boundaries for ``neighboring'' are based largely on use 
of the 100-year floodplain. The agencies concluded that the use of the 
riparian area was unnecessarily complicated and that as a general 
matter, waters in the riparian area will also be in the 100-year 
floodplain. Further, should the riparian area on occasion extend beyond 
the 100-year floodplain, the agencies have the ability to perform a 
case-specific significant nexus analysis on a water out to 4,000 feet 
from the ordinary high water mark or high tide line of a traditional 
navigable water, interstate water, the territorial sea, impoundment, or 
tributary. The agencies have drawn these lines based on their technical 
expertise and experience in order to provide a rule that is practical 
to understand and implement and protects those waters that 
significantly affect the chemical, physical, or biological integrity of 
traditional navigable waters, interstate waters, or the territorial 
seas. Because science indicates that connectivity is on a gradient, the 
agencies have also identified limited circumstances in which waters 
that do not meet the definition of ``neighboring'' may be determined on 
a case-specific basis to have a significant nexus. See section IV.I.
    First, the rule establishes as ``neighboring'' waters that occur 
within 100 feet from traditional navigable

[[Page 37083]]

waters, interstate waters, the territorial seas, impoundments, and 
tributaries.
    Second, the rule utilizes a specific floodplain and also 
establishes maximum distances for purposes of ``neighboring.'' Studies 
have found that waters within the floodplain are dynamically connected 
and frequently interact with the downstream traditional navigable 
water, interstate water, territorial sea, impoundment, or tributary. 
Some commenters indicated that a specific floodplain or other 
designation should be set to define the outer boundary of 
``neighboring.'' Further, some commenters requested that the 100-year 
floodplain designation be used to define the outer boundary of 
adjacency because the public understands this concept. Several 
commenters recommended that FEMA or NRCS maps be used to support the 
analysis as these maps are easily accessible to the public. Because 
FEMA maps exist for many areas of the country and the NRCS Soil Survey 
maps do as well, the agencies decided that defining ``neighboring'' 
based in part on a particular floodplain or recurrence interval was a 
reasonable means of ensuring the consistency and certainty that is 
important to the public and for implementation of the CWA. In drawing 
lines, the agencies chose the 100-year floodplain in part because FEMA 
and NRCS together have generally mapped large portions of the United 
States, and these maps are publicly available, well-known and well-
understood.
    Because the 100-year floodplain can be very wide in some areas of 
the country, particularly near large rivers, the agencies chose to 
provide increased clarity and certainty while ensuring that waters that 
provide important functions significantly affecting the chemical, 
physical, and biological integrity of the downstream traditional 
navigable waters, interstate waters, or the territorial seas are 
protected by establishing a 1,500 foot maximum distance for neighboring 
waters in the rule. Waters within the 100-year floodplain to a maximum 
of 1,500 feet of the ordinary high water mark are adjacent without 
regard to the presence of berms or other barriers. However, because the 
science demonstrates that floodplain waters provide important functions 
for downstream waters, the agencies have established a provision under 
paragraph (a)(8) for case-specific significant nexus evaluations of 
waters located in the 100-year floodplain of a traditional navigable 
water, interstate water, or the territorial seas beyond 1,500 feet.
    The rule also establishes a separate bright line for including as 
jurisdictional those waters that occur within 1,500 feet of tidally-
influenced traditional navigable waters or the territorial seas.
    The proposal defined ``neighboring'' to include waters with a 
surface connection to jurisdictional waters and some commenters 
recommended eliminating surface hydrologic connectivity as a basis for 
adjacency. The definition of neighboring does not include a provision 
defining ``neighboring'' based on a surface hydrologic connection. 
However, waters with confined surface hydrologic connections are 
considered adjacent where they are bordering, contiguous, or 
neighboring a traditional navigable water, interstate water, the 
territorial seas, impoundment, or covered tributary. For example, a 
water with a confined surface hydrologic connection to a traditional 
navigable water that is 1,200 feet from the high tide line of that 
water would meet the definition of neighboring and be considered an 
adjacent water. In circumstances where a water does not meet the 
definition of neighboring but is located within the 100-year floodplain 
of a traditional navigable water, interstate water, or the territorial 
seas, or within 4,000 feet of a jurisdictional water, a confined 
surface hydrologic connection may be an important factor in evaluating 
a case-specific significant nexus under paragraph (a)(8). See section 
H. below.
    The proposal defined ``neighboring'' to include waters connected 
with a shallow subsurface connection, and some commenters recommended 
eliminating subsurface hydrologic connectivity as a basis for 
adjacency. For example, some commenters asserted that, because the CWA 
does not apply to groundwater, the agencies do not have the authority 
to assert jurisdiction over waters connected to other ``waters of the 
United States'' via a shallow subsurface hydrologic connection. Some 
commenters were concerned that the distinction between ``groundwater'' 
and a ``shallow subsurface connection'' was unclear and questioned 
whether using a shallow subsurface connection as a basis for adjacency 
is contradictory to excluding groundwater--including groundwater 
drained through subsurface drainage systems--as a ``water of the United 
States.'' Some commenters supported use of shallow subsurface 
connectivity for adjacency, since the significant nexus test would be 
employed to make the determination of jurisdiction. Several commenters 
suggested that the rule should protect groundwater and shallow 
subsurface flow, due to its connectivity to other ``waters of the 
United States'' and particularly since altering it could affect the 
downstream waters. A few commenters simply requested clarifications 
regarding issues such as how to determine whether a subsurface 
connection exists; the meaning of ``shallow;'' distinguishing between 
``shallow'' and ``deep;'' whether there were any boundaries on 
adjacency via hydrologic connectivity; and determining whether the 
connection was ``sufficient'' to establish adjacency. In order to 
provide more certainty to the public, the rule does not include a 
provision defining neighboring based on shallow subsurface flow, though 
such flow may be an important factor in evaluating a water on a case-
specific basis under paragraph (a)(8), as appropriate.
    Some commenters expressed concern that the agencies' proposed 
definition of ``neighboring,'' ``riparian area,'' and ``floodplain'' 
would mean that all land within the floodplain or riparian area would 
become regulated. In fact, only waters, not land, in the floodplain or 
riparian area would have been considered adjacent under the proposed 
rule. Similarly, under the final rule, only waters, not land, are 
adjacent. In response, the agencies have eliminated the definitions of 
floodplain and riparian area and have provided a definition of 
neighboring which is clear that only waters in specified circumstances 
may be ``waters of the United States.''
    The agencies also eliminated a parenthetical from the existing 
``adjacent wetlands'' regulatory provision. The phrase ``other than 
waters that are themselves wetlands'' was intended to preclude 
asserting CWA jurisdiction over wetlands that were simply adjacent to a 
non-jurisdictional wetland. Such waters do not meet the definition of 
``adjacent'' under the rule since waters must be adjacent to a 
traditional navigable water, interstate water, the territorial seas, 
impoundment, or covered tributary, so the phrase is unnecessary and 
confusing. With this change, the agencies are protecting all waters 
that meet the definition of ``adjacent'' as ``waters of the United 
States,'' and eliminating confusion caused by the parenthetical. For 
example, where the 100-year floodplain is greater than 1,500 feet, all 
wetlands within 1,500 feet of the tributary's ordinary high water mark 
are jurisdictional because they are ``neighboring'' to the tributary, 
regardless of the wetlands' position relative to each other.
    Some commenters stated that the proposed rule was an expansion of 
jurisdiction because it would change the

[[Page 37084]]

provision from ``adjacent wetlands'' to ``adjacent waters.'' The 
agencies acknowledge that under the existing regulation, the adjacency 
provision applied only to wetlands adjacent to ``waters of the United 
States.'' However, also under the existing regulation, ``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. This provision of the 
existing regulation reflected the agencies' interpretation at the time 
of the jurisdiction of the CWA to extend to the maximum extent 
permissible under the Commerce Clause of the Constitution. Therefore, 
while the language of the specific adjacency provision in the final 
rule may have changed from wetlands to waters, that does not represent 
an expansion of jurisdiction as a whole in comparison to the existing 
regulation, since adjacent non-wetland waters would have been subject 
to jurisdiction under the ``other waters'' provision. The final rule 
does not protect all waters that were protected under the ``other 
waters'' provision of the existing regulation, and therefore the 
inclusion of adjacent ponds, for example, in the ``adjacent waters'' 
provision of the final rule does not reflect an overall expansion of 
jurisdiction when compared to the existing regulation.
3. How do science and law support the rule?
    Based on a review of the scientific literature and the agencies' 
expertise and experience the agencies determined that the categories of 
waters discussed below are integrally linked to the chemical, physical, 
or biological functions of waters to which they are adjacent and 
downstream to the traditional navigable waters, interstate waters or 
the territorial seas. Therefore, the agencies determined that the 
waters defined as adjacent have a significant nexus with traditional 
navigable waters, interstate waters or the territorial seas and are 
thus ``waters of the United States.'' Additional information, including 
citations, can be found in section III of the preamble, the Science 
Report, and the Technical Support Document for the rule.
a. Waters that are Bordering or Contiguous
    As discussed in section III above, wetlands, ponds, lakes, oxbows, 
impoundments, and similar water features that are bordering or 
contiguous perform a myriad of critical chemical and biological 
functions associated with the downstream traditional navigable waters, 
interstate waters, or the territorial seas. Such waters are integrally 
linked with the jurisdictional waters to which they are adjacent. 
Because of their close physical proximity to nearby jurisdictional 
waters, bordering or contiguous waters readily exchange their waters 
through the saturated soils surrounding the traditional navigable 
water, interstate water, the territorial seas, impoundment, or covered 
tributary or through surface exchange. This commingling of waters 
allows bordering or contiguous waters to both provide chemically 
transformed waters to streams and to absorb excess stream flow, which 
in turn can significantly affect downstream traditional navigable 
waters, interstate waters, or the territorial seas. The close proximity 
also allows for the direct exchange of biological materials, including 
organic matter that serves as part of the food web of downstream 
traditional navigable waters, interstate waters, or the territorial 
seas. Waters that are bordering or contiguous are often located on the 
floodplain or within the riparian area of the waters to which they are 
adjacent. Bordering or contiguous waters include those that directly 
abut a traditional navigable water, interstate water, the territorial 
seas, impoundment, or covered tributary. The Science Report and the 
Technical Support Document demonstrate that such waters are physically, 
chemically, and biologically integrated with downstream traditional 
navigable waters, interstate waters, or the territorial seas and 
significantly affect their integrity.
b. Waters Separated From Other ``Waters of the United States'' by 
Constructed Dikes or Barriers, Natural River Berms, Beach Dunes and the 
Like
    Adjacent waters separated from a traditional navigable water, 
interstate water, the territorial seas, impoundment, or covered 
tributary by constructed dikes or barriers, natural river berms, beach 
dunes, and the like continue to have a significant effect on downstream 
traditional navigable waters, interstate waters, or the territorial 
seas, either alone or in combination with other ``adjacent waters.'' 
Such waters 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 the flow of water 
through the soil pores, or via over-topping, where water from the 
nearby traditional navigable water, interstate water, the territorial 
seas, impoundment, or covered tributary periodically overtops the berm 
or other similar feature. Berm-like landforms known as natural levees 
occur naturally and do not isolate adjacent wetlands from the streams 
that form them. 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. Man-made levees and similar structures also do not isolate 
``adjacent waters.'' Waters, including wetlands, separated from a 
jurisdictional water by a natural or man-made berm serve many of the 
same functions as other ``adjacent waters.'' Furthermore, even in cases 
where a hydrologic connection may not exist, there are other important 
considerations, such as chemical and biological functions, that result 
in a significant nexus between the adjacent wetlands or waters and the 
nearby ``waters of the United States,'' and traditional navigable 
waters, interstate waters, or the territorial seas. On this point, 
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. For instance, covered adjacent 
waters behind berms can still serve important water quality functions, 
serving to filter pollutants and sediment before they reach downstream 
waters. Wetlands and open waters behind berms, where the system is 
extensive, can help reduce the impacts of storm surges caused by 
hurricanes. Such ``adjacent waters,'' including wetlands, separated 
from waters by berms and the like maintain ecological connection with 
those waters. It is not the existence of the dike, levee, and the like 
that makes these waters jurisdictional. Adjacent waters separated from 
the tributary network by constructed dikes or barriers, natural river 
berms, beach dunes, and the like continue to have a hydrologic 
connection to downstream waters.

[[Page 37085]]

Waters behind berms and the like can significantly affect the chemical, 
physical, and biologic integrity of traditional navigable waters, 
interstate waters, or the territorial seas.
c. Waters Within 100 Feet
    All wetlands, ponds, lakes, oxbows, impoundments, and similar water 
features that are located in whole or in part within 100 feet of the 
ordinary high water mark of a jurisdictional water perform a myriad of 
critical chemical, physical, and biological functions associated with 
the downstream traditional navigable water, interstate water or the 
territorial seas and therefore the agencies have determined that they 
are ``neighboring'' and thus ``waters of the United States.'' Waters 
within 100 feet of a jurisdictional water are often located within the 
riparian area and are often connected via surface and shallow 
subsurface hydrology to the water to which they are adjacent. While the 
SAB was clear that distance is not the only factor that influences 
connections and their effects downstream, due to their close proximity 
to jurisdictional waters, waters within 100 feet are often located 
within a landscape position that allows for them to receive and process 
surface and shallow subsurface flows before they reach streams and 
rivers. These waters individually and collectively affect the integrity 
of downstream waters by acting primarily as sinks that retain 
floodwaters, sediments, nutrients, and contaminants that could 
otherwise negatively impact the condition or function of downstream 
waters. Wetlands and open waters within close proximity of 
jurisdictional waters improve water quality through assimilation, 
transformation, or sequestration of nutrients, sediment, and other 
pollutants that can affect the integrity of downstream traditional 
navigable waters, interstate waters, or the territorial seas. These 
waters, including wetlands, also provide important habitat for aquatic-
associated species to forage, breed, and rest.
    In order to provide greater clarity and consistency and based on a 
review of the science and the agencies' expertise and experience, the 
agencies identified a 100 foot threshold for neighboring waters to a 
traditional navigable water, interstate water, territorial sea, 
tributary, or impoundment. Further, the agencies determined that there 
is a significant nexus with the downstream traditional navigable 
waters, interstate waters, or the territorial seas, and these 
``adjacent waters'' are ``waters of the United States.'' With respect 
to provision of water quality benefits downstream, non-floodplain 
waters within close proximity of the stream network often are able to 
have more water quality benefits than those located at a distance from 
the stream. Many studies indicate that the primary water quality and 
habitat benefits will generally occur within a several hundred foot 
zone of a water. In addition, the scientific literature indicates that 
to be effective, contaminant removal needs to occur at a reasonable 
distance prior to entry into the downstream traditional navigable 
waters, interstate waters, or the territorial seas. Some studies also 
indicate that fish, amphibians (e.g., frogs, toads), reptiles (e.g., 
turtles), and small mammals (e.g., otters, beavers, etc.) will use at 
least a 100 foot zone for foraging, breeding, nesting, and other life 
cycle needs.
    Based on a review of the scientific literature and the agencies' 
expertise and experience, there is clear evidence that the identified 
waters within 100 feet of the ordinary high water mark of a 
jurisdictional water, even when located outside the floodplain, perform 
critical processes and functions discussed in section III above. All 
waters within 100 feet of a jurisdictional water significantly affect 
the chemical, physical, or biological integrity of the waters to which 
they are adjacent, and those waters in turn significantly affect the 
chemical, physical, or biological integrity of the downstream 
traditional navigable waters, interstate waters, or the territorial 
seas. The agencies established a 100 foot threshold from the water's 
lateral limit in the definition of neighboring because, based on the 
agencies' expertise and experience implementing the CWA and in light of 
the science, the agencies concluded this was a reasonable and practical 
boundary within which to conclude the waters clearly significantly 
affected the integrity of traditional navigable waters, interstate 
waters, or the territorial seas, and these ``adjacent waters'' are 
``waters of the United States.''
d. Floodplain Waters Within 1,500 Feet
    As discussed in section III above, wetlands and open waters that 
are neighboring perform a myriad of critical chemical and biological 
functions associated with the downstream traditional navigable waters, 
interstate waters, or the territorial seas. The scientific literature 
supports that wetlands and open waters in floodplains are chemically, 
physically, and biologically connected to downstream traditional 
navigable waters, interstate waters, or the territorial seas and 
significantly affect the integrity of such waters. The Science Report 
concludes that wetlands and open waters located in ``floodplains are 
physically, chemically and biologically integrated with rivers via 
functions that improve downstream water quality, including the 
temporary storage and deposition of channel-forming sediment and woody 
debris, temporary storage of local ground water that supports baseflow 
in rivers, and transformation and transport of stored organic matter.'' 
Science Report at ES-2 to ES-3. Such waters act as the most effective 
buffer to protect downstream waters from nonpoint source pollution 
(such as nitrogen and phosphorus), provide habitat for breeding fish 
and aquatic insects that also live in streams, and retain floodwaters, 
sediment, nutrients, and contaminants that could otherwise negatively 
impact the condition or function of downstream waters.
    For waters in the 100-year floodplain within 1,500 feet of the 
ordinary high water mark of a traditional navigable water, interstate 
water, the territorial seas, impoundment, or covered tributary, the 
agencies determine there is a significant nexus with the downstream 
traditional navigable waters, interstate waters, or the territorial 
seas and these waters are critical to protect the downstream waters. 
Based on a review of the scientific literature, the agencies' technical 
expertise and experience, and the implementation value of drawing clear 
lines, the rule establishes a boundary for floodplain waters to meet 
the definition of ``neighboring'' and be ``waters of the United 
States'' by rule. This boundary was established in order to protect 
vitally important waters within a watershed while at the same time 
providing a practical and implementable rule. The agencies are not 
determining that waters in the floodplain farther than 1,500 feet from 
the ordinary high water mark never have a significant nexus. Rather, 
the agencies are using their technical expertise to promulgate a 
practical rule that draws reasonable boundaries in order to protect the 
waters that most clearly have a significant nexus while minimizing 
uncertainty about the scope of ``waters of the United States.'' Because 
waters beyond these boundaries may have a significant nexus, the rule 
also establishes areas in which a case-specific significant nexus 
determination must be made. See section IV.H.
e. Waters Within 1,500 Feet of Tidally-Influenced Traditional Navigable 
Waters or the Territorial Seas or the Great Lakes
    Many tidally-influenced waters do not have floodplains, so the 
agencies

[[Page 37086]]

include a separate provision within the definition of ``neighboring'' 
to protect the ``adjacent'' waters that have a significant nexus to 
tidally-influenced traditional navigable waters or the territorial seas 
or the Great Lakes. Under Riverside Bayview and Justice Kennedy's 
opinion in Rapanos, waters adjacent to traditional navigable waters, 
including the territorial seas, are ``waters of the United States.'' 
Because the connection to a tidally-influenced traditional navigable 
water, the territorial seas, or the Great Lakes is so close, the rule 
defines ``neighboring'' to include waters within 1,500 feet of the high 
tide line or the ordinary high water mark of the Great Lakes. Wetlands, 
ponds, lakes, oxbows, impoundments, and similar water features within 
1,500 feet of these waters are physically connected to such waters by 
surface and shallow subsurface flow. As demonstrated in section III 
above, these waters perform a myriad of critical chemical and 
biological functions associated with these nearby waters to which they 
are adjacent.
    These waters in combination significantly affect the integrity of 
the connected tidally influenced traditional navigable water or the 
territorial seas or the Great Lakes by acting primarily as sinks that 
retain floodwaters, sediments, nutrients, and contaminants that could 
otherwise negatively impact the condition or function of those waters. 
Like floodplain waters, the scientific literature supports that 
wetlands and other similar waters within close proximity improve water 
quality through assimilation, transformation, or sequestration of 
nutrients, sediment, and other pollutants that can affect downstream 
water quality. These waters also provide important habitat for aquatic-
associated species to forage, breed, and rest in.
    For example, wetlands dominated by grass-like vegetation that occur 
in depressional areas between sand dunes or beach ridges along the 
territorial seas and the Great Lakes shoreline are dependent upon these 
waters for their water source. The waters, including wetlands, 
generally form when water levels of the territorial seas fall or the 
Great Lakes drop, creating swales that support a diverse mix of wetland 
vegetation and many endangered and threatened species. Many studies 
demonstrate that these waters have been shown to act in concert with 
the rising and lowering of the tide, and that the critical functions 
provided by these waters are similar and play an important role in 
maintaining the chemical, physical, or biological integrity of the 
nearby traditional navigable waters, interstate waters, or the 
territorial seas because of the hydrological and ecological connections 
to and interactions with those waters.
    Science demonstrates that distance is a factor in the connectivity 
and the strength of connectivity of wetlands and open waters to 
downstream waters. Thus, waters that are more distant generally have 
less opportunity to be connected to downstream waters. Wetlands and 
open waters closer to the stream network generally will have greater 
hydrologic and biological connectivity than waters located farther from 
the same network. For instance, waters that are more closely proximate 
have a greater opportunity to contribute flow. Via their hydrologic 
connectivity, they also have chemical connectivity to and effects on 
these downstream waters and are more likely to impact water quality due 
to their close distance. Waters more closely located to these waters 
are also more likely to be biologically connected to such waters more 
frequently and by more species, including amphibians and other aquatic 
animals. Because tidally-influenced traditional navigable waters, the 
territorial seas, and the Great Lakes are generally much larger in size 
than other jurisdictional waters, the agencies believe that a 1,500 
foot threshold is a reasonable distance to capture most wetlands and 
open waters that are so closely linked to these waters that they can 
properly be considered adjacent as neighboring waters.
    Based on a review of the scientific literature and the agencies' 
expertise and experience, there is clear evidence waters within 1,500 
feet of these waters, even when located outside the floodplain, perform 
critical processes and functions discussed in section III above. The 
agencies established a 1,500 foot threshold from the water's lateral 
limit, which would be either the high tide line or the ordinary high 
water mark, in the definition of neighboring because, based on the 
agencies' expertise and experience implementing the CWA and in light of 
the science, the agencies concluded this was a reasonable and practical 
boundary within which to conclude the waters most clearly significantly 
affected the integrity of the traditional navigable water or the 
territorial seas, and these covered adjacent waters are ``waters of the 
United States.'' Waters located within the 100-year floodplain of a 
traditional navigable water, interstate water, or the territorial seas, 
and waters located more than 1,500 feet and less than 4,000 feet from 
the ordinary high water mark of a traditional navigable water, 
interstate water, the territorial seas, an impoundment, or a tributary, 
may still be determined to have a significant nexus on a case-specific 
basis under paragraph (a)(8) of the rule and therefore be a ``water of 
the United States.'' See section IV.H.

H. Case-Specific ``Waters of the United States''

    The rule establishes two exclusive circumstances under which case-
specific determinations will be made for whether a water has a 
``significant nexus'' and is therefore a ``water of the United 
States.'' The proposed rule included a broad provision that allowed for 
a case-specific determination of significant nexus for any water that 
was not categorically jurisdictional or excluded. Many commenters 
expressed concern that such a broad opportunity for case-specific 
``waters of the United States'' determinations would lead to too much 
uncertainty about the jurisdictional status of waters in broad areas 
throughout the country. The agencies have greatly reduced the extent of 
waters subject to this individual review by carefully incorporating the 
scientific literature and by utilizing agency expertise and experience 
to draw boundaries. The rule provides for case-specific determinations 
under more narrowly targeted circumstances based on the agencies' 
assessment of the importance of certain specified waters to the 
chemical, physical, and biological integrity of traditional navigable 
waters, interstate waters, and the territorial seas.
    First, the rule identifies at paragraph (a)(7) five subcategories 
of waters (Prairie potholes, Carolina and Delmarva bays, pocosins, 
western vernal pools in California, and Texas coastal prairie wetlands) 
that the agencies have determined are ``similarly situated'' for 
purposes of a significant nexus determination. Second, the rule 
identifies at paragraph (a)(8) specific circumstances under which 
waters will be subject to a case-specific significant nexus 
determination but for which the agencies have not made a ``similarly 
situated'' determination: Waters within the 100-year floodplain of a 
traditional navigable water, interstate water, or the territorial seas, 
and waters within 4,000 feet of the high tide line or the ordinary high 
water mark of a traditional navigable water, interstate water, the 
territorial seas, impoundments, or tributaries, as defined. If any 
water meets the definition of ``adjacent'' waters it is jurisdictional 
under paragraph (a)(6) and no case-specific significant nexus is 
required. Waters that do not fall within the six categorically 
jurisdictional waters identified in paragraph (a)(1) through

[[Page 37087]]

(a)(6) of the rule or within these two case-specific provisions are not 
``waters of the United States.''
    This section first discusses the five subcategories of waters that 
the agencies determine are ``similarly situated'' for purposes of a 
significant nexus determination; second, the 100-year floodplain and 
4,000 foot boundaries under which waters will be subject to a case-
specific significant nexus determination but for which the agencies 
have not made a ``similarly situated'' determination; third, the 
definition of ``significant nexus'' and how the case-specific 
significant nexus determinations will be made under these two 
provisions; and, finally, the revisions made to the rule with respect 
to case-specific determinations and major comments.
1. Waters Determined To Be ``Similarly Situated'' by Rule for Which a 
Case-Specific Significant Nexus Determinations Is Required
    In the rule, paragraph (a)(7) specifies the subcategories of waters 
(Prairie potholes, Carolina and Delmarva bays, pocosins, western vernal 
pools in California, and Texas coastal prairie wetlands) that, if they 
are not otherwise jurisdictional under paragraphs (a)(1) through 
(a)(6), the agencies determine to be ``similarly situated'' by rule. In 
the proposal the agencies sought comment on a number of options to 
address remaining waters that did not fit within the jurisdictional 
categories, including whether to conclude that other waters were 
``similarly situated'' in certain areas of the country or whether to 
conclude that specified subcategories of waters were jurisdictional. 79 
FR 22215, 22216. The agencies concluded that waters within the five 
subcategories were ``similarly situated'' in the areas of the country 
in which they are located. The rationale for this determination is 
discussed above in Section III. Under paragraph (a)(7), Prairie 
potholes, Carolina and Delmarva bays, pocosins, western vernal pools in 
California, and Texas coastal prairie wetlands are jurisdictional when 
they have a significant nexus to a traditional navigable water, 
interstate water, or the territorial seas. Waters subject to normal 
farming, silviculture, and ranching activities that are within these 
subcategories will be assessed consistent with this provision of the 
rule. Waters in these subcategories are not jurisdictional as a class 
under the rule. However, because the agencies determined that these 
subcategories of waters are ``similarly situated,'' the waters within 
the specified subcategories that are not otherwise jurisdictional under 
paragraph (a)(6) of the rule must be assessed in combination with all 
waters of the same subcategory in the region identified by the 
watershed that drains to the nearest point of entry of a traditional 
navigable water, interstate water, or the territorial seas (hereinafter 
referred to as the point of entry watershed).
    When performing a case-specific significant nexus evaluation for a 
water in the paragraph (a)(7) subcategories, the rule establishes which 
waters must be considered in combination. The similarly situated waters 
identified in the subparagraphs will be combined with other waters in 
the same subparagraph located in a single point of entry watershed. For 
example, under paragraph (a)(7) only western vernal pools can be 
analyzed with other western vernal pools in the same point of entry 
watershed. Waters identified in the subparagraphs that are otherwise 
jurisdictional under the rule cannot be considered in combination with 
paragraph (a)(7) waters for purposes of a case-specific significant 
nexus determination under paragraph (a)(7). Individual waters of the 
specified subcategories may be jurisdictional under other paragraphs of 
this rule (e.g., a Prairie pothole that sits on a state border is an 
interstate water under paragraph (a)(2) or a western vernal pool that 
meets the definition of adjacent under paragraph (a)(6)). Where those 
individual waters are jurisdictional under paragraph (a)(1) through 
(a)(6) by rule, no case-specific significant nexus analysis is 
required. The rule also states that waters in paragraph (a)(7) shall 
not be combined with waters jurisdictional under paragraph (a)(6). 
Essentially, while Prairie potholes are an identified subcategory under 
paragraph (a)(7), that identification does not affect a Prairie pothole 
that borders a covered tributary and is jurisdictional as an adjacent 
water under paragraph (a)(6). Additionally, a Prairie pothole that is 
jurisdictional under paragraph (a)(6) cannot be combined with Prairie 
potholes that require a case-specific jurisdictional analysis under 
paragraph (a)(7) since ``adjacent waters'' have already been determined 
to have a significant nexus by rule. Finally, waters within the 
specified subcategories in paragraph (a)(7) are assessed under 
paragraph (a)(7) not under paragraph (a)(8); waters within the 
specified subcategories that are within the 100-year flood plain of a 
traditional navigable water, interstate water, or the territorial seas 
or within the 4,000 foot boundary established for case-specific 
determinations under paragraph (a)(8) remain ``similarly situated'' 
waters under paragraph (a)(7). These similarly situated waters are 
evaluated in combination for their effect on the chemical, physical, or 
biological integrity of traditional navigable waters, interstate 
waters, or the territorial seas. Additional details about the case-
specific significant nexus analysis are found in section 4 below.
2. Waters Within the 100-Year Floodplain of a Traditional Navigable 
Water, Interstate Water, or the Territorial Seas and Waters Within 
4,000 Foot Boundary for Which a Case-Specific Significant Nexus 
Determination Is Required
    Paragraph (a)(8) in the rule specifies that a water that does not 
otherwise meet the definition of adjacency is evaluated on a case-
specific basis for significant nexus under this paragraph where it is 
located within the 100-year floodplain of a traditional navigable 
water, interstate water, or the territorial seas or within 4,000 feet 
of the high tide line or ordinary high water mark of a traditional 
navigable water, interstate water, the territorial seas, impoundment, 
or covered tributary. Although these waters are not considered 
similarly situated by rule, waters under this paragraph can be 
determined on a case-specific basis to be similarly situated. This is a 
change from the proposal which would have allowed for a similarly 
situated analysis and significant nexus determination for any water, 
anywhere in the region. Under the rule, the waters specified in 
paragraph (a)(7) and waters that meet the requirements in paragraph 
(a)(8) are the only waters for which a case-specific significant nexus 
determination may be made.
    Under paragraph (a)(8), only waters that are within the 100-year 
floodplain of a traditional navigable water, interstate water, or the 
territorial seas or within the 4,000 foot boundary can be evaluated on 
a case-specific basis for significant nexus to a traditional navigable 
water, interstate water, or the territorial seas. If a portion of the 
water is located within the 100-year floodplain of a traditional 
navigable water, interstate water, or the territorial seas or 4,000 
feet of the ordinary high water mark or high tide line of a traditional 
navigable water, interstate water, the territorial seas, impoundment, 
or covered tributary, the entire water will be considered to be within 
the boundaries for paragraph (a)(8) and will undergo a case-specific 
significant nexus determination. Under this provision, if the 100-year 
floodplain of a traditional navigable water,

[[Page 37088]]

interstate water, or the territorial seas extends beyond 4,000 feet of 
the ordinary high water mark, a water, that is not otherwise 
jurisdictional under the rule, within that floodplain will be evaluated 
under the 100-year floodplain boundary of paragraph (a)(8). A water 
within the boundaries must be evaluated on a case-specific basis for 
not only a significant nexus but also for a determination of whether 
there are any waters with which the waters is similarly situated. 
Waters identified in paragraph (a)(8) may not be combined with waters 
identified in paragraph (a)(6) for purposes of the significant nexus 
analysis, but may be combined with similarly situated waters located in 
the same point of entry watershed. If waters identified in paragraph 
(a)(8) also meet the definition of adjacency under paragraph (a)(6), 
they are jurisdictional as ``adjacent waters'' and do not need a case-
specific significant nexus analysis. Under paragraph (a)(8), for 
example, the agencies would evaluate on a case-specific basis whether a 
low-centered polygonal tundra and patterned ground bog in an area with 
a small floodplain and located beyond the 1,500 foot boundary but 
within the 100-year floodplain of a traditional navigable water, 
interstate water, or the territorial seas or within the 4,000 foot 
boundary, or a wetland in which normal farming, ranching, or 
silviculture activities occur, as those terms are used in section 
404(f) of the Clean Water Act and its implementing regulations, has a 
significant nexus as defined in the rule.
    Waters identified in the subcategories in paragraph (a)(7) are 
evaluated under paragraph (a)(7) only; the provisions of paragraph 
(a)(8), including the boundaries in paragraph (a)(8), do not apply to 
paragraph (a)(7) waters. The significant nexus analysis for waters 
under paragraph (a)(8) will then consider the waters individually or, 
if it is determined that there are similarly situated waters, as a 
group of waters within a point of entry watershed for their effect on 
the chemical, physical, or biological integrity of traditional 
navigable waters, interstate waters, or the territorial seas.
    Some commenters asked how wetlands underlain by permafrost would be 
treated under this rule. Waters subject to case-specific review under 
paragraph (a)(8) will include areas determined to meet the technical 
definition of ``wetlands'' because they have the required hydrology, 
vegetation, and soils. The presence of permafrost is not itself 
determinative of whether a particular area satisfies the three 
parameter requirement needed to be wetlands under the rule. This is 
true under existing regulations and remains unchanged in this rule. 
Because the definition of wetland does not change under the rule, the 
agencies do not anticipate the rule will alter the current scope of CWA 
jurisdiction over wetlands underlain by permafrost.
a. Summary of Rationale for Case-Specific Significant Nexus Analysis 
Within 100-Year Floodplain of a Traditional Navigable Water, Interstate 
Water, or the Territorial Seas
    As discussed in Section III, above, the scientific literature 
supports that wetlands and open waters in floodplains are physically, 
chemically, and biologically connected to downstream traditional 
navigable waters, interstate waters, or the territorial seas and 
significantly affect the integrity of such waters. The Science Report 
concludes that wetlands and open waters located in ``floodplains are 
physically, chemically and biologically integrated with rivers via 
functions that improve downstream water quality, including the 
temporary storage and deposition of channel-forming sediment and woody 
debris, temporary storage of local ground water that supports baseflow 
in rivers, and transformation and transport of stored organic matter.'' 
Science Report at ES-2 to ES-3. As described in the Science Report and 
the Technical Support Document, such waters act as the most effective 
buffer to protect downstream waters from nonpoint source pollution 
(such as nitrogen and phosphorus), provide habitat for breeding fish 
and aquatic insects that also live in streams, and retain floodwaters, 
sediment, nutrients, and contaminants that could otherwise negatively 
impact the condition or function of downstream waters. As discussed 
above, in defining waters as adjacent, and therefore categorically 
jurisdictional, the agencies established a 1,500 foot boundary for 
waters located within the 100-year floodplain of a traditional 
navigable water, interstate water, the territorial seas, impoundment, 
or covered tributary in order to protect vitally important waters while 
at the same time providing a practical and implementable rule. In light 
of the science on the functions provided by floodplain waters and 
wetlands, waters and wetlands within the 100-year floodplain of 
traditional navigable waters, interstate waters, or the territorial 
seas are likely to provide those functions for traditional navigable 
waters, interstate waters, or the territorial seas. However, because 
the 100-year floodplain of a traditional navigable water can, in some 
case be quite large, the agencies concluded it was reasonable to 
subject waters and wetlands in the 100-year floodplain that are beyond 
1,500 feet of the ordinary high water mark, and therefore do not meet 
the definition of ``neighboring,'' to a case-specific significant nexus 
analysis rather than concluding that such waters are categorically 
jurisdictional. This inclusion of a case-specific analysis for such 
floodplain waters is supported by the SAB. The SAB concluded that 
``distance should not be the sole indicator used to evaluate the 
connection of `other waters' to jurisdictional waters.'' SAB 2014b at 
3. In allowing the case-specific evaluation of waters within the 100-
year floodplain of a traditional navigable water, interstate water, or 
the territorial seas that do not meet the definition of adjacency, the 
agencies are allowing for the functional relationship of those 
floodplain waters to be considered regardless of distance. The SAB also 
supported the Science Report's conclusion that ``the scientific 
literature strongly supports the conclusions that streams and 
`bidirectional' floodplain wetlands are physically, chemically, and/or 
biologically connected to downstream navigable waters; however, these 
connections should be considered in terms of a connectivity gradient.'' 
SAB 2014a at 1. In addition, the SAB noted, ``the literature review 
does substantiate the conclusion that floodplains and waters and 
wetlands in floodplain settings support the physical, chemical, and 
biological integrity of downstream waters.'' Id. at 3.
    The agencies do not anticipate that there will be numerous 
circumstances in which this provision will be utilized because 
relatively few traditional navigable waters will have floodplains 
larger than 4,000 feet (the other threshold in paragraph (a)(8) for 
waters regardless of floodplain). Further, the agencies recognize that 
extensive areas of the nation's floodplains have been affected by 
levees and dikes which reduce the scope of flooding. In these 
circumstances, the scope of the 100-year floodplain is also reduced and 
is reflected in FEMA mapping used by the agencies. In circumstances 
where there is little or no alteration of the floodplain and it remains 
relatively broad, the agencies will explicitly consider distance 
between the water being evaluated and traditional navigable water, 
interstate water, or the territorial seas when making a case-specific 
significant nexus determination. Based on the science concerning the 
important functions provided by floodplain waters and wetlands, the 
agencies established this provision to ensure that truly

[[Page 37089]]

important waters may still be protected on a case-specific basis. By 
using the 100-year floodplain and limiting the provision to traditional 
navigable waters, interstate waters, or the territorial seas, the 
agencies are reasonably balancing the protection of waters that may 
have a significant nexus with the goal of providing additional 
certainty.
b. Summary of Rationale for Case-Specific Significant Nexus Analysis 
Within 4,000 Foot Boundary
    The agencies establish a provision in the rule for case-specific 
significant nexus determinations because the agencies concluded that 
some waters located beyond the distance limitations established for 
``adjacent waters'' can have significant chemical, physical, and 
biological connections to and effects on traditional navigable waters, 
interstate waters, or the territorial seas. The agencies reasonably 
identified the 4,000 foot boundary for these case-specific significant 
nexus determinations by balancing consideration of the science and the 
agencies' expertise and experience in making significant nexus 
determinations with the goal of providing clarity to the public while 
protecting the environment and public health. The agencies' experience 
has shown that the vast majority of waters where a significant nexus 
has been found, and which are therefore important to protect to achieve 
the goals of the Act, are located within the 4,000 foot boundary. 
Moreover, because of the unique status under the CWA of traditional 
navigable waters, interstate waters, and the territorial seas, the 100-
year floodplain boundary for these waters provides another means of 
identifying on a case-specific basis those waters that significantly 
affect traditional navigable waters, interstate waters or the 
territorial seas. The agencies' balancing of these considerations is 
consistent with the statute and the Supreme Court opinions. The 
agencies decided that it is important to promulgate a rule that not 
only protects the most vital of our Nation's waters, but one that is 
practical and provides sufficient boundaries so that the public 
reasonably understands where CWA jurisdiction ends.
    The agencies' decision to establish a provision that authorizes 
case-specific significant nexus analysis for waters within 4,000 feet 
is based on a number of factors. These waters may be located within the 
floodplain of a traditional navigable water, interstate water, the 
territorial seas, impoundment, or covered tributary. Section IV.G. and 
the Technical Support Document discuss the importance of floodplain 
waters on the chemical, physical, and biological integrity of 
downstream traditional navigable waters, interstate waters, or the 
territorial seas. For purposes of clarity and to provide regulatory 
certainty, the agencies decided to use distance boundaries within the 
100-year floodplain to define adjacency for floodplain waters. Under 
the rule, the only floodplain waters that are specifically identified 
as being jurisdictional as ``adjacent'' are those located in whole or 
in part within the 100-year floodplain and not more than 1,500 feet of 
the ordinary high water mark of jurisdictional waters.
    Similarly, due to the many functions that waters located within 
4,000 feet of the high tide line of a traditional navigable water or 
the territorial seas provide and their often close connections to the 
surrounding traditional navigable waters, science supports the 
agencies' determination that such waters are rightfully evaluated on a 
case-specific basis for significant nexus to a traditional navigable 
water or the territorial seas. Waters within 4,000 feet of the ordinary 
high water mark of a traditional navigable water, interstate water, the 
territorial seas, impoundment, or covered tributary may fall within the 
riparian areas of such waters. As discussed in section IV.G., in 
response to comments regarding the uncertainty of the term ``riparian 
area,'' the agencies removed the term from the definition of 
``neighboring.'' However, the agencies continue to recognize that 
science is clear that wetlands and open waters in riparian areas 
individually and cumulatively can have a significant effect on the 
chemical, physical, or biological integrity of downstream waters. Thus, 
the rule allows for a case-specific determination of significant nexus 
for waters located within 4,000 feet of the high tide line or the 
ordinary high water mark of a traditional navigable water, interstate 
water, the territorial seas, impoundment, or covered tributary.
    The agencies have always recognized that adjacency is bounded by 
proximity, and the rule adds additional clarity to adjacency by 
bounding what can be considered neighboring. The science is clear that 
a water's proximity to downstream waters influences its impact on those 
waters. The Science Report states, ``[s]patial proximity is one 
important determinant of the magnitude, frequency and duration of 
connections between wetlands and streams that will ultimately influence 
the fluxes of water, materials and biota between wetlands and 
downstream waters.'' Science Report at ES-11. Generally, waters that 
are closer to a jurisdictional water are more likely to be connected to 
that water than waters that are farther away. A case-specific analysis 
for waters located within 4,000 feet of the high tide line or the 
ordinary high water mark of a traditional navigable water, interstate 
water, the territorial seas, impoundment, or covered tributary allows 
such waters to be considered jurisdictional only where they meet the 
significant nexus requirements. Even where not within a 100-year 
floodplain, waters within 4,000 feet of the high tide line or the 
ordinary high water mark of a traditional navigable water, interstate 
water, the territorial seas, impoundment, or covered tributary can have 
significant chemical, physical, and biological connections with 
traditional navigable waters, interstate waters, or the territorial 
seas.
    As noted previously, in response to comments concerned that there 
were no bounds in the proposed rule on how far a surface hydrologic 
connection could be for purposes of adjacency, the agencies did not 
include surface hydrologic connections as its own factor for 
determining adjacency in the final rule. Such connections, however, are 
relevant in a case-specific significant nexus determination under 
paragraph (a)(8). For example, waters located within 4,000 feet of the 
high tide line or the ordinary high water mark of a traditional 
navigable water, interstate water, the territorial seas, impoundment, 
or covered tributary that contribute confined surface flow to a 
downstream water can have important hydrologic connections to and 
effects on that downstream water such as the attenuation and cycling of 
nutrients that would otherwise effect downstream water quality.
    The agencies' decision to establish the case-specific provision at 
paragraph (a)(8), including the boundaries, was also informed by the 
knowledge that waters located within 4,000 feet of the high tide line 
or the ordinary high water mark of a traditional navigable water, 
interstate water, the territorial seas, impoundment, or covered 
tributary can have a confined surface or shallow subsurface connection 
to such a water. In order to provide the clarity and certainty that 
many commenters requested regarding ``adjacent waters,'' the rule does 
not define ``neighboring'' to include all waters with confined surface 
or shallow subsurface connections.
    However, the agencies recognize that the science demonstrates that 
waters with a confined surface or shallow subsurface connection to 
jurisdictional

[[Page 37090]]

waters can have important effects on downstream waters. For purposes of 
a case-specific significant nexus analysis under the rule, a shallow 
subsurface hydrologic connection is lateral water flow over a 
restricting layer in the top soil horizons, or a shallow water table 
which fluctuates within the soil profile, sometimes rising to or near 
the ground surface. In addition, water can move within confined man-
made subsurface conveyance systems such as drain tiles and storm 
sewers, and in karst topography. Confined subsurface systems can move 
water, and potential contaminants, directly to surface waters and 
rapidly without the opportunity for nutrient or sediment reduction 
along the pathway.
    Shallow subsurface connections move quickly through the soil and 
impact surface water directly within hours or days rather than the 
years it may take long pathways to reach surface waters. See Technical 
Support Document. Tools to assess shallow subsurface flow include 
reviewing the soils information from the NRCS Soil Survey, which is 
available for nearly every county in the United States. When assessing 
whether a water within the 4,000 foot boundary performs any of the 
functions identified in the rule's definition of significant nexus, the 
significant nexus determination can consider whether shallow subsurface 
connections contribute to the type and strength of functions provided 
by a water or similarly situated waters. However, neither shallow 
subsurface connections nor any type of groundwater, shallow or deep, 
are themselves ``waters of the United States.''
    The proposed rule did not set a distance threshold for case-
specific waters to be evaluated for a significant nexus. Some 
commenters argued that there should be a limitation on areas subject to 
case-specific analysis while others contended that the agencies lack 
discretion to set regulatory limits that would exclude from 
jurisdiction any water meeting the significant nexus test. The agencies 
disagree that the agencies lack the authority to establish reasonable 
boundaries to determine what areas are subject to case-specific 
significant nexus analysis. Nothing in the CWA or case law mandates 
that the agencies require every water feature in the nation be subject 
to analysis for significant nexus. The Supreme Court has made clear 
that the agencies have the authority and responsibility to determine 
the limits of CWA jurisdiction, and establishing boundaries based on 
agency judgment, expertise and experience in administering the statute 
is at the core of the agencies authority and discretion.
    After weighing the scientific information about these waters' 
connectivity and importance to protecting downstream waters, the 
agencies' considerable experience making jurisdictional determinations, 
the objective of enhancing regulatory clarity and consistent with the 
statute and the caselaw, the agencies decided to set a boundary of 
4,000 feet for case-specific significant nexus analysis for waters that 
do not otherwise meet the requirements of paragraphs (a)(1) through 
(a)(7). Tying this provision for case-specific significant nexus 
analysis to distance informed by the science, and the agencies' 
experience and expertise, as spatial proximity is a key contributor to 
connectivity among waters. Science Report at ES-11. Distance is by no 
means the sole factor, and aquatic functions will play a prominent role 
in determining whether specific waters covered under this aspect of 
paragraph (a)(8) have a significant nexus. In light of the role spatial 
proximity plays in connectivity and the objective of enhancing 
regulatory clarity, predictability and consistency, the agencies 
conclude that establishing a boundary for this aspect of waters subject 
to case-specific significant nexus analysis based on distance is 
reasonable.
    While, for purposes of this national rule, distance is a reasonable 
and appropriate measure for identifying where this case-specific 
significant nexus analysis will be conducted, the science does not 
point to any particular bright line delineating waters that have a 
significant nexus from those that do not. The Science Report concluded 
that connectivity of streams and wetlands to downstream waters occurs 
along a gradient. The evidence unequivocally demonstrates that the 
stream channels and floodplain wetlands or open waters that together 
form river networks are clearly connected to downstream waters in ways 
that profoundly influence downstream water integrity. The connectivity 
and effects of non-floodplain wetlands and open waters are more 
variable and thus more difficult to address solely from evidence 
available in peer-reviewed studies. Science Report at ES-5. Because of 
this variability, with respect to waters that are not covered by 
paragraphs (a)(1) through (a)(7) of the rule, the science does not 
provide a precise point along the continuum at which waters provide 
only speculative or insubstantial functions to downstream waters.
    Like connectivity itself, there is also a continuum of outcomes 
associated with picking a distance threshold. A smaller threshold 
increases the likelihood that waters that could have a significant 
nexus will not be analyzed and therefore not subject to the Act; a 
larger threshold reduces that possibility, but also means that agency 
and the public's resources are expended conducting significant nexus 
analyses on waters that have a lower likelihood of meriting the Act's 
protection.
    Recognizing that there is no optimal line, in selecting both the 
100-year floodplain for and the 4,000 foot boundaries the agencies 
looked principally to the extensive experience the Corps has gained in 
making significant nexus determinations since the Rapanos decision. As 
noted in Section III above, since the Rapanos decision, the agencies 
have developed extensive experience making significant nexus 
determinations, and that experience and expertise informed the judgment 
of the agencies in establishing both the 100-year floodplain boundary 
and the 4,000 foot boundary. The agencies have made determinations in 
every state in the country, for a wide range of waters in a wide range 
of conditions. The vast majority of the waters that the Corps has 
determined have a significant nexus are located within 4,000 feet of a 
jurisdictional tributary, traditional navigable or interstate water, or 
the territorial seas. Therefore, the agencies conclude that the 100-
year floodplain and 4,000 foot boundaries in the rule will sufficiently 
capture for analysis those waters that are important to protect to 
achieve the goals of the Clean Water Act.
    The agencies acknowledge that, as with any meaningful boundary, 
some waters that could be found jurisdictional lie beyond the boundary 
and will not be analyzed for significant nexus. The agencies minimize 
that risk by also establishing a provision in paragraph (a)(8) for 
case-specific significant nexus analysis of waters located within the 
100-year floodplain of a traditional navigable water, interstate water, 
or the territorial seas. While in the agencies' experience the vast 
majority of wetlands with a significant nexus are located within the 
4,000 foot boundary, it is the agencies' experience that there are a 
few waters that have been determined to be jurisdictional that are 
located beyond this boundary, typically due to a surface or shallow 
subsurface hydrologic connections. Nonetheless, the agencies have 
weighed these considerations and concluded that the value of enhancing 
regulatory clarity, predictability and consistency through a distance 
limit outweigh the likelihood that a distinct minority of waters that 
might be shown

[[Page 37091]]

to meet the significant nexus test will not be subject to analysis. In 
the agencies' experience, requiring an evaluation of significant nexus 
for waters covered by paragraph (a)(8) should capture the vast majority 
of waters having a significant nexus to the downstream waters. The 
agencies therefore conclude that that adoption of the 4,000 foot 
boundary is reasonable.
    The rule's requirements for these waters, coupled with those for 
``adjacent waters,'' create an integrated approach that tailors the 
regulatory regime based on the science and the agencies' policy 
objectives. Determining by rule that covered adjacent waters have a 
significant nexus follows the science, achieves regulatory clarity and 
predictability, and avoids expenditure of agency and public resources 
on case-specific significant nexus analysis. Similarly, providing for 
case-specific significant nexus analysis for waters that are not 
adjacent but within the 4,000 foot distance limit, as well as those 
within the 100-year floodplain of a traditional navigable water, 
interstate water, or the territorial seas, is consistent with science 
and agency experience, will ensure protection of the important waters 
whose protection will advance the goals of the Clean Water Act, and 
will greatly enhance regulatory clarity for agency staff, regulated 
parties, and the public.
    For these reasons, the agencies decided to allow case-specific 
determinations of significant nexus for waters located within the 100-
year floodplain of a traditional navigable water, interstate water, or 
the territorial seas and for waters located within 4,000 feet of the 
high tide line or the ordinary high water mark of a traditional 
navigable water, an interstate water, the territorial seas, an 
impoundment, or a covered tributary. Under the rule, these waters are 
jurisdictional only where they individually or cumulatively (if it is 
determined that there are other similarly situated waters) have a 
significant nexus to traditional navigable waters, interstate waters, 
or the territorial seas. Additional scientific and policy rationale for 
including such waters as waters that can be evaluated on a case-
specific basis can be find in the Technical Support Document.
    The agencies emphasize that they fully support efforts by States 
and tribes to protect under their own laws any additional waters, 
including locally special waters that may not be within the 
jurisdiction of the CWA as the agencies have interpreted its scope in 
this rule. Indeed, the promulgation of the 100-year floodplain and 4000 
foot boundaries for purposes of a case-specific analysis of significant 
nexus does not foreclose states from acting consistent with their state 
authorities to establish protection for waters that fall outside of the 
protection of the CWA. In promulgating the 4,000 foot boundary, the 
agencies have balanced protection and clarity, scientific uncertainties 
and regulatory experience, and established a line that is, in their 
judgment, reasonable and consistent with the statute and its goals and 
objectives.
3. Case-Specific Significant Nexus Determinations
    Only waters identified in paragraphs (a)(7) or (a)(8) of the rule 
require a case-specific determination of significant nexus. This 
section discusses the definition of significant nexus in the rule and 
how the agencies will make case-specific significant nexus 
determinations under the rule.
a. Definition of Significant Nexus
    Paragraph (c)(5) of the rule defines the term ``significant nexus'' 
to mean a significant effect (more than speculative or insubstantial) 
on the chemical, physical, or biological integrity of a traditional 
navigable water, interstate water, or the territorial seas. Waters, 
including wetlands, are evaluated either alone, or in combination with 
other similarly situated waters in the region, based on the functions 
the evaluated waters perform. Functions to be considered for the 
purposes of determining significant nexus are sediment trapping, 
nutrient recycling, pollutant trapping, transformation, filtering and 
transport, retention and attenuation of floodwaters, runoff storage, 
contribution of flow, export of organic matter, export of food 
resources, and provision of life-cycle dependent aquatic habitat (such 
as foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in traditional navigable waters, interstate 
waters, or the territorial seas.
    The agencies' definition of significant nexus is based upon the 
language in SWANCC and Rapanos. The definition is also consistent with 
current practice, where field staff evaluate the functions of the 
waters in question and the effects of these functions on downstream 
waters. In order to add clarity and transparency to the definition of 
significant nexus, the agencies have listed in the definition the 
functions that will be considered in a significant nexus analysis. 
These functions are consistent with the agencies' scientific 
understanding of the functioning of aquatic ecosystems. A water does 
not need to perform all of the functions listed in paragraph (c)(5) in 
order to have a significant nexus. Depending upon the particular water 
and the functions it provides, if a water, either alone or in 
combination with similarly situated waters, performs just one function, 
and that function has a significant impact on the integrity of a 
traditional navigable water, interstate water, or the territorial seas, 
that water would have a significant nexus.
    Case-specific determinations of significant nexus require paragraph 
(a)(7) or (a)(8) waters to be evaluated either alone, or in combination 
with other similarly situated waters in the region. In the rule, the 
agencies interpret the phrase ``in the region'' to mean the watershed 
that drains to the nearest traditional navigable water, interstate 
water, or the territorial seas through a single point of entry. See 
Section III. In circumstances where the single point of entry watershed 
includes waters that are identified under paragraph (a)(7) and waters 
that are subject to analysis under paragraph (a)(8), those waters will 
be analyzed separately under the provisions of those paragraphs.
    In a case-specific analysis of significant nexus, the agencies 
determine whether the water they are evaluating, in combination with 
other similarly situated waters in the region, has a significant effect 
on the chemical, physical, or biological integrity of the nearest 
traditional navigable water, interstate water, or the territorial seas. 
As noted previously, the agencies evaluate the listed functions in 
paragraph (c)(5) as part of that evaluation to determine if the water 
has an impact that is more than speculative or insubstantial.
b. Conducting Case-Specific Significant Nexus Determinations Under 
Paragraphs (a)(7) and (a)(8)
    The significant nexus analysis for waters assessed under paragraphs 
(a)(7) and (a)(8) is a three-step process: First, the region for the 
significant nexus analysis must be identified--under the rule, it is 
the watershed which drains to the nearest traditional navigable water, 
interstate water or territorial sea; second, any similarly situated 
waters must be identified--under the rule, that is waters that function 
alike and are sufficiently close to function together in affecting 
downstream waters; and third, the waters are evaluated individually or 
in combination with any identified similarly situated waters in the 
single point of entry watershed to determine if they significantly 
impact the chemical, physical or biological integrity of the 
traditional navigable water, interstate water or the territorial seas.

[[Page 37092]]

i. ``In the Region''--The Point of Entry Watershed
    As discussed in Section III of the preamble and established in the 
definition of ``significant nexus,'' the region for purposes of a 
significant nexus analysis is the watershed that drains to the nearest 
traditional navigable water, interstate water, or the territorial seas. 
The first step of the analysis is to identify the point of entry 
watershed that the water being evaluated under paragraphs (a)(7) or 
(a)(8) drains to. This point of entry approach identifies the nearest 
traditional navigable water, interstate water, or the territorial seas 
that the water being evaluated and any similarly situated waters flow 
to and delineates the watershed of that nearest traditional navigable 
water, interstate water, or the territorial seas. The point of entry 
watershed is the area drained by the nearest traditional navigable 
water, interstate water, or the territorial seas and is typically 
defined by the topographic divides between one traditional navigable 
water, interstate water, or the territorial seas and another.
    Available mapping tools, such as those that are based on the NHD, 
topographic maps, and elevation data, can be used to demarcate 
boundaries of the single point of entry watershed. As discussed in 
Section III and in the Technical Support Document, the single point of 
entry watershed represents the scientifically appropriate sized area 
for conducting a case-specific significant nexus evaluation in most 
cases.
    In the arid West, the agencies recognize there may be situations 
where the single point of entry watershed is very large, and it may be 
reasonable to evaluate all similarly situated waters in a smaller 
watershed. Under those circumstances, the agencies may demarcate 
adjoining catchments surrounding the water to be evaluated that, 
together, are generally no smaller than a typical 10-digit hydrologic 
unit code (HUC-10) watershed in the same area. The area identified by 
this combination of catchments would be the ``region'' used for 
conducting a significant nexus evaluation under paragraphs (a)(7) or 
(a)(8) under those situations. The basis for such an approach in very 
large single point of entry watersheds in the arid West should be 
documented in the jurisdictional determination.
ii. ``Similarly Situated''
    Second, the agencies determine if the water or waters to be 
evaluated are similarly situated. The waters identified in paragraph 
(a)(7) are similarly situated by rule and shall be combined with other 
waters of the same category located in the same watershed that drains 
to the nearest traditional navigable water, interstate water, or the 
territorial seas with no need for a case-specific similarly situated 
finding. Under paragraph (a)(7), only waters of the same subparagraph 
in the point of entry watershed can be considered as similarly 
situated. For example, only pocosins may be evaluated with other 
pocosins in the same point of entry watershed. Pocosins in different 
point of entry watersheds cannot be combined, and pocosins cannot be 
combined with Carolina bays under paragraph (a)(7), even where they 
occur in the same point of entry watershed.
    Unlike waters evaluated under paragraph (a)(7), the waters 
specified at paragraph (a)(8) require a determination whether they are 
similarly situated. Under this step, the agencies apply factors in the 
determination of when waters evaluated under paragraph (a)(8) should be 
considered either individually or in combination for purposes of a 
significant nexus analysis. A determination of ``similarly situated'' 
requires an evaluation of whether a group of waters in the region that 
meet the distance thresholds set out under paragraph (a)(8) can 
reasonably be expected to function together in their effect on the 
chemical, physical, or biological integrity of downstream traditional 
navigable waters, interstate waters, or the territorial seas.
    Similarly situated waters can be identified as sufficiently close 
together for purposes of this paragraph of the regulation when they are 
within a contiguous area of land with relatively homogeneous soils, 
vegetation, and landform (e.g., plain, mountain, valley, etc.). In 
general, it would be inappropriate, for example, to consider waters as 
``similarly situated'' under paragraph (a)(8) if these waters are 
located in different landforms, have different elevation profiles, or 
have different soil and vegetation characteristics, unless the waters 
perform similar functions and are located sufficiently close to a 
``water of the United States'' to allow them to consistently and 
collectively function together to affect a traditional navigable water, 
interstate water, or the territorial seas. In determining whether 
waters under paragraph (a)(8) are sufficiently close to each other the 
agencies will also consider hydrologic connectivity to each other or a 
jurisdictional water.
    In determining whether groups of waters under paragraph (a)(8) 
perform ``similar functions'' the agencies will consider functions such 
as habitat, water storage, sediment retention, and pollution 
sequestration. In addition, consideration of wetland/water type and 
landscape location are relevant for determining if the waters are 
similarly situated. For example, Texas coastal sand sheet wetlands that 
form a complex of wetlands with other wetlands of the same type on the 
landscape and are densely located may very well be similarly situated 
and considered in combination with other Texas coastal sand sheet 
wetlands in the same single point of entry watershed. However, under 
paragraph (a)(8), waters do not need to be of the same type (as they do 
in paragraph (a)(7)) to be considered similarly situated. As described 
above, waters are similarly situated under paragraph (a)(8) where they 
perform similar functions or are located sufficiently close to each 
other, regardless of type. The agencies will consider the hydrologic, 
geomorphic, and ecological characteristics and circumstances of the 
waters under consideration. Examples include: Documentation of 
chemical, physical, or biological interactions of the similarly 
situated waters; aerial photography; USGS and state and local 
topographical or terrain maps and information; NRCS soil survey maps 
and data; other available geographic information systems (GIS) data; 
National Wetlands Inventory maps where wetlands meet the CWA 
definition; and state and local information. The evaluation will use 
any available site information and pertinent field observations where 
available, relevant scientific studies or data, or other relevant 
jurisdictional determinations that have been completed in the region.
    Only those waters that do not meet the requirements in paragraph 
(a)(1) through (a)(6) are to be considered in case-specific significant 
nexus determinations; subcategory waters that meet the provisions in 
paragraph (a)(1) through (a)(6) are per se jurisdictional without the 
need for a significant nexus determination. For example, waters that 
are identified under paragraph (a)(6) are adjacent and are not subject 
to a case-specific significant nexus evaluation under paragraph (a)(7) 
or (a)(8). Waters evaluated under paragraph (a)(7) cannot be combined 
with waters identified in paragraph paragraph (a)(6) or (a)(8), and 
waters evaluated under paragraph (a)(8) cannot be combined with waters 
identified in paragraph (a)(6) or (a)(7). For example, Prairie potholes 
being evaluated under paragraph (a)(7) may not be combined with Prairie 
potholes that are per se jurisdictional under paragraph (a)(6) that 
meet the definition

[[Page 37093]]

of adjacent. When a water meets the specifications at both paragraphs 
(a)(7) and (a)(8), it can only be evaluated under paragraph (a)(7). 
That is, for example, if a wetland is a Western vernal pool and is also 
within 4,000 feet of the ordinary high water mark of a covered 
tributary, it can only be assessed for significant nexus under 
paragraph (a)(7) in combination with other Western vernal pools in the 
point of entry watershed. Unlike paragraph (a)(8), there is no distance 
threshold for waters evaluated under paragraph (a)(7)--that is, waters 
in the paragraph (a)(7) subcategories that are more than 4,000 feet 
from the high tide line or the ordinary high water mark of a 
traditional navigable water, interstate water, the territorial seas, 
impoundment, or covered tributary or are beyond the 100-year floodplain 
of an traditional navigable water, interstate water, or the territorial 
seas are to be included in combination in a significant nexus analysis.
iii. Significant Nexus Analysis for Paragraph (a)(7) and (a)(8) Waters
    Third, the agencies evaluate waters individually or in combination 
with any identified similarly situated waters in the single point of 
entry watershed to determine if they significantly impact the chemical, 
physical, or biological integrity of the traditional navigable water, 
interstate water, or the territorial seas. For purposes of determining 
significant nexus under paragraph (a)(7), all waters of the specified 
subcategory are to be considered in combination in the point of entry 
watershed, as those waters are similarly situated. For purposes of 
determining significant nexus under paragraph (a)(8), depending on the 
results of step two, a water within the boundaries in paragraph (a)(8) 
is evaluated either alone or in combination with other similarly 
situated waters in the region. For example, in the case where the 
agencies have determined that a particular water under paragraph (a)(8) 
is not similarly situated, it is evaluated individually for significant 
nexus; the water cannot be aggregated if it is not similarly situated 
with other such waters.
    The analysis will include an evaluation of the functions listed in 
paragraph (c)(5) of the rule, which defines significant nexus. A water 
has a significant nexus when any single function or combination of 
functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest traditional 
navigable water, interstate water, or the territorial seas. A water may 
be determined to have a significant nexus based on performing any of 
the following functions: sediment trapping, nutrient recycling, 
pollutant trapping, transformation, filtering, and transport, retention 
and attenuation of floodwaters, runoff storage, contribution of flow, 
export of organic matter, export of food resources, or provision of 
life cycle dependent aquatic habitat (such as foraging, feeding, 
nesting, breeding, spawning, or use as a nursery area) for species 
located in a traditional navigable water, interstate water, or the 
territorial seas.
    For purposes of paragraph (c)(5)(ix), a species is located in a 
traditional navigable water, interstate water, or the territorial seas 
if such a water is a typical type of habitat for at least part of the 
life cycle of the species. For example, amphibians and many reptiles 
can use a traditional navigable water, interstate water, or the 
territorial seas for part of their life cycle needs.
    When 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, 
a variety of factors will influence the chemical, physical, or 
biological connections the water has with the downstream traditional 
navigable water, interstate water, or the territorial seas, including 
distance from a jurisdictional water, the presence of surface or 
shallow subsurface hydrologic connections, and density of waters of the 
same type (if it has been concluded that such waters can be evaluated 
in combination). The likelihood of a significant connection is greater 
with increasing size and decreasing distance from the identified 
traditional navigable water, interstate water, or the territorial seas, 
as well as with increased density of the waters for such waters that 
can be considered in combination as similarly situated waters. In 
addition, the presence of a surface or shallow subsurface hydrologic 
connection can influence the impact that a water has with downstream 
waters.
    In many cases, the presence of a hydrologic connection increases 
the strength of the impact of the downstream traditional navigable 
water, interstate water, or the territorial seas. However, a hydrologic 
connection is not necessary to establish a significant nexus, because, 
as Justice Kennedy stated, in some cases the lack of a hydrologic 
connection would be a sign of the water's function in relationship to 
the traditional navigable water, interstate water, or the territorial 
seas. These functional relationships include retention of floodwaters 
or pollutants that would otherwise flow downstream to the traditional 
navigable water, interstate water, or the territorial seas. See 547 
U.S. at 775 (citations omitted) (J. Kennedy) (``it may be the absence 
of an interchange of waters prior to the dredge and fill activity that 
makes protection of the wetlands critical to the statutory scheme''). 
The Science Report concludes, ``[s]ome effects of non-floodplain 
wetlands on downstream waters are due to their isolation, rather than 
their connectivity. Wetland `sink' functions that trap materials and 
prevent their export to downstream waters (e.g., sediment and entrained 
pollutant removal, water storage) result because of the wetland's 
ability to isolate material fluxes.'' Science Report at ES-4. For 
example, a report that reviewed the results of multiple scientific 
studies concluded that depressional wetlands lacking a surface outlet 
functioned together to significantly reduce or attenuate flooding. See 
Science Report and Technical Support Document. Even when they lack a 
surface hydrologic connection to downstream traditional navigable 
waters, interstate waters, or the territorial seas, Prairie potholes, 
for instance, cumulatively can store large volumes of water, impacting 
streamflow and reducing flooding downstream, and several studies have 
quantified the large storage capacity of Prairie pothole complexes. 
This water storage function is estimated to hold tens of millions of 
cubic meters of water, including for example Prairie potholes located 
in the watersheds of Devils Lake and the Red River of the North, which 
have both had a long history of flooding. Where Prairie potholes lack a 
surface hydrologic connection, this water storage capacity is 
particularly effective in reducing downstream flooding and can have a 
significant effect on downstream traditional navigable waters, 
interstate waters, or the territorial seas. Thus, even when lacking a 
surface hydrologic connection, a water can still have a significant 
effect on the chemical or the biological integrity of downstream 
traditional navigable waters, interstate waters, or the territorial 
seas.
    The rule recognizes that not all waters have the requisite 
connection to traditional navigable waters, interstate waters, or the 
territorial seas sufficient to be determined jurisdictional. Waters 
with a significant nexus must significantly affect the chemical, 
physical, or biological integrity of a downstream traditional navigable 
water,

[[Page 37094]]

interstate water, or the territorial seas, and the requisite nexus must 
be more than ``speculative or insubstantial.'' Rapanos at 780.
    Evidence of chemical connectivity and the effect on waters can be 
found by identifying the properties of the water in comparison to the 
identified traditional navigable water, interstate water, or the 
territorial seas; 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 ``water of the United 
States,'' and through it to a traditional navigable water, interstate 
water, or the territorial seas. In addition, relevant factors 
influencing chemical connectivity include hydrologic connectivity (see 
physical factors, below), surrounding land use and land cover, the 
landscape setting, and deposition of chemical constituents (e.g., 
acidic deposition).
    Evidence of physical connectivity and the effect on traditional 
navigable waters, interstate waters, or the territorial seas can be 
found by identifying evidence of physical connections, such as flood 
water or sediment retention (flood prevention). Presence of indicators 
of hydrologic connections between the other water and jurisdictional 
water are also indicators of a physical connection. Factors influencing 
physical connectivity include rain intensity, duration of rain events 
or wet season, soil permeability, and distance of hydrologic connection 
between the paragraph (a)(7) or (a)(8) water and the traditional 
navigable water, interstate water, or the territorial seas, depth from 
surface to water table, and any preferential flowpaths.
    Evidence of biological connectivity and the effect on waters can be 
found by identifying: Resident aquatic or semi-aquatic species present 
in the case-specific water and the tributary system (e.g., amphibians, 
aquatic and semi-aquatic reptiles, aquatic birds); 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 case-specific water, and if so whether such dispersal 
extends to the tributary system or beyond or from the tributary system 
to the case-specific water. Factors influencing biological connectivity 
include species' life history traits, species' behavioral traits, 
dispersal range, population size, timing of dispersal, distance between 
the case-specific water and a traditional navigable water, interstate 
water, or the territorial seas, the presence of habitat corridors or 
barriers, and the number, area, and spatial distribution of habitats. 
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 biological connectivity for purposes 
of this rule.
    For practical administrative purposes, the rule does not require 
evaluation of all similarly situated waters under paragraph (a)(7) or 
(a)(8) when concluding that those waters have a significant nexus to a 
traditional navigable water, interstate water, or territorial sea. When 
a subset of similarly situated waters provides a sufficient science-
based justification to conclude presence of a significant nexus, for 
efficiency purposes a significant nexus analysis need not unnecessarily 
require time and resources to locate and analyze all similarly situated 
waters in the entire point of entry watershed. For example, if a single 
Carolina bay or a group of Carolina bays in a portion of the point of 
entry watershed is determined to significantly affect the chemical, 
physical, or biological integrity of a traditional navigable water, 
interstate water, or the territorial seas, the analysis does not have 
to document all of the similarly situated Carolina bays in the 
watershed in order to conduct the significant nexus analysis. A 
conclusion that significant nexus is lacking may not be based on 
consideration of a subset of similarly situated waters because under 
the significant nexus standard the inquiry is how the similarly 
situated waters in combination affect the integrity of the downstream 
water.
    While the rule is clear that waters that are jurisdictional by rule 
cannot be combined with waters subject to a case-specific significant 
nexus analysis, the analysis may appropriately include the evaluation 
of functions of paragraph (a)(8) waters that reach covered waters 
through paragraph (a)(6) waters without consideration of the functions 
contributed by those paragraph (a)(6) waters. The hydrologic 
connections between paragraph (a)(8) waters and a covered tributary and 
eventually to a traditional navigable water, interstate water, or the 
territorial seas, can often occur through an adjacent water. This 
hydrologic connection is an appropriate part of the case-specific 
analysis as to whether the paragraph (a)(8) waters, alone or in 
combination with any similarly situated paragraph (a)(8) waters in the 
point of entry watershed, provide those functions downstream such that 
they significantly affect the chemical, physical or biological 
integrity of the traditional navigable water, interstate water, or the 
territorial seas. For example, when evaluating a wetland that is 2,500 
feet from the ordinary high water mark of an paragraph (a)(5) water and 
that has surface or shallow subsurface connections to downstream 
traditional navigable waters, interstate waters, or the territorial 
seas via a wetland that is adjacent to an paragraph (a)(4) water, the 
existence of those connections is not ignored. However, while a water's 
connections to the traditional navigable water, interstate water, or 
the territorial seas through paragraph (a)(5) through (a)(7) waters can 
be considered in the significant nexus analysis in order to determine 
whether the functions of the paragraph (a)(8) waters are provided 
downstream, only the functions of the water, along with any similarly 
situated waters, being evaluated under paragraph (a)(8) on downstream 
water integrity can be included in the significant nexus analysis.
    The administrative record for a jurisdictional determination for a 
water under paragraph (a)(7) or (a)(8) will include available 
information supporting the determination. In addition to location and 
other descriptive information regarding the water at issue, the record 
will include an explanation of the rationale for the jurisdictional 
conclusion and a description of the information used. Relevant 
information can come from many sources, and need not always be specific 
to the water whose jurisdictional status is being evaluated. Studies of 
the same type of water or similarly situated waters can help to inform 
a significant nexus analysis as long as they are applicable to the 
water being evaluated. In the case of paragraph (a)(8) waters, the 
administrative record will include the rationale behind the similarly 
situated analysis, including an explanation of the data or information 
examined.
    The agencies expect that where waters are determined to be 
similarly situated in a single point of entry watershed, such similarly 
situated waters will often be found jurisdictional through the case-
specific analysis of significant nexus. However, case-specific factors 
such as distance to the traditional navigable water, interstate water, 
or the territorial seas; density or number of similarly situated 
waters; individual and cumulative size of the similarly situated 
waters; soil permeability; climate; etc., may be considered in the 
determination, and there could be cases where even considering these 
waters in combination with similarly situated waters will not

[[Page 37095]]

be sufficient for waters to have a significant nexus.
    Within a single point of entry watershed, over a period of time 
there will likely be multiple jurisdictional determinations. For 
paragraph (a)(7) waters, if a case-specific significant nexus 
determination has been made in the point of entry watershed, all waters 
in the subcategory in the point of entry watershed are jurisdictional. 
For paragraph (a)(8) waters, the case-specific significant nexus 
analyses must use information used in previous jurisdictional 
determinations, and if a significant nexus has been established for one 
water in the watershed, then other similarly situated waters in the 
watershed would also be found to have a significant nexus. This is 
because under Justice Kennedy's test, similarly situated waters in the 
region should be evaluated together. A positive significant nexus 
determination would then apply to all similarly situated waters within 
the point of the watershed. A negative case-specific significant nexus 
evaluation under paragraph (a)(7) or (a)(8) of all similarly situated 
waters in the point of entry watershed applies to all similarly 
situated waters in that watershed. However, as noted above, a 
conclusion that significant nexus is lacking may not be based on 
consideration of a subset of similarly situated waters, because under 
the significant nexus standard the inquiry is how the similarly 
situated waters in combination affect the integrity of the downstream 
water. The documentation for each case should be complete enough to 
support the specific jurisdictional determination, including an 
explanation of which waters were considered together as similarly 
situated and in the same region.
4. Summary of Revisions to Case-Specific Determinations of ``Waters of 
the United States'' and Major Comments
a. Significant Nexus
    Some commenters stated concerns over the potential for inconsistent 
application of the significant nexus analysis in a jurisdictional 
determination. To address this concern within the regulatory framework, 
the agencies provide more detail regarding the definition of 
significant nexus in the rule and list the specific functions that will 
be considered in the analysis. This approach provides individual 
regulators who conduct the analysis clear and consistent parameters 
that they will consider during their review in making jurisdictional 
determinations and provides transparency to the regulated public over 
which factors will be considered.
    Overall, there was support for the concept of the single point of 
entry watershed as the interpretation of ``in the region.'' Several 
commenters supported the approach that the single point of entry 
watershed was an appropriate scale to use to measure effect on 
traditional navigable waters, interstate waters, or the territorial 
seas. Other commenters felt the single point of entry watershed was too 
small to capture all the benefits that waters that do not meet the 
definition of adjacency contribute. Some of the SAB panel members 
thought that because surface and ground-watershed units may not align, 
watersheds might be problematic for defining ``in the region.'' These 
panel members suggested that a more scientifically justified approach 
would include surface and subsurface waters in a watershed delineation. 
The agencies have retained the single point of entry watershed from the 
proposed rule as the appropriate unit of analysis for significant nexus 
in the final rule as these watersheds are more easily understood and 
easier to delineate than those that map subsurface waters as the SAB 
suggested.
    With respect to the agencies' approach to ``similarly situated 
waters,'' commenters offered support for assessing waters in 
combination based on their type and function, particularly waters such 
as Prairie potholes. Conversely, several commenters found that the 
ability to aggregate waters that do not meet the definition of 
adjacency is over-reaching and causes uncertainty to the regulated 
public. Some commenters also attributed uncertainty in which waters 
were regulated to subjectivity in review by Federal regulator(s). 
Similarly, some commenters were concerned that waters eligible for 
protection were based on an individual analyst's interpretation and 
wanted to know how the agencies would address consistency and potential 
bias. In response, the rule lists in paragraph (a)(7) a limited number 
of subcategories of waters where waters of the specified types have 
been determined by rule to be similarly situated for a significant 
nexus analysis. This will add consistency, predictability, and clarity, 
as the rule explicitly states that such waters are similarly situated 
for purposes of the significant nexus analysis. For waters identified 
under paragraph (a)(8), the agencies have established two limitations: 
Waters within the 100-year floodplain of a traditional navigable water, 
interstate water, or the territorial seas, and waters within 4,000 foot 
feet of a traditional navigable water, interstate water, the 
territorial seas, impoundment, or covered tributary. The agencies also 
have established within the definition of significant nexus at 
paragraph (c)(5) criteria for determining whether waters are similarly 
situated and should therefore be analyzed in combination. Waters 
identified under paragraph (a)(8) are similarly situated when they 
function alike and are sufficiently close to function together in 
affecting downstream waters. The agencies have not determined that such 
waters are categorically similarly situated, so the agencies will base 
their case-specific determinations of whether a particular water has 
any similarly situated waters on the available information and science. 
The rule also clarifies that paragraph (a)(8) waters cannot be 
considered similarly situated with ``adjacent waters,'' which are 
jurisdictional by rule, and paragraph (a)(7) waters, which have been 
determined to be similarly situated by rule. These parameters will 
reduce inconsistency in reviews and add clarity.
    Similarly, several commenters expressed concern that landowners 
would not know which water bodies on their property are subject to CWA 
jurisdiction due to aggregation, as waters on their property may be 
considered similarly situated with waters located off-site. While the 
rule does not eliminate the use of case-specific significant nexus 
analyses, and the concern arises from Justice Kennedy's phrase 
``similarly situated,'' the parameters placed on waters requiring a 
case-specific determination and the clearer definition of significant 
nexus address the concerns about uncertainty and inconsistencies in 
reviews. In particular, waters that are not either one of the five 
identified subcategories in paragraph (a)(7) or within the thresholds 
in paragraph (a)(8) cannot be subject to a case-specific significant 
nexus analysis under the rule. Generally, jurisdictional determinations 
are conducted at the request of an applicant or landowner for specific 
waters. While the agencies cannot arbitrarily depart from a 
determination that waters are ``similarly situated,'' landowners may 
provide new information to inform subsequent jurisdictional 
determinations. In addition, owners with questions regarding 
jurisdiction of waters on their property may always consult their local 
Corps District or EPA Regional Office, which is not a change from 
longstanding practice.

[[Page 37096]]

b. Case-Specific Determinations
    The rule provides more regulatory certainty by narrowing the scope 
of waters that can be assessed under a case-specific significant nexus 
evaluation as compared to the proposal. These changes still allow the 
scientific value of specific waters not covered in paragraph (a)(1) 
through (a)(6) to be evaluated on a case-specific basis.
    In the proposal, the agencies solicited comment regarding a variety 
of approaches to the category of waters subject to a case-specific 
significant nexus analysis. In addition, the agencies solicited comment 
on additional scientific research and data that might further inform 
decisions about these waters. In particular the agencies solicited 
information about whether current scientific research and data 
regarding particular types of waters are sufficient to support the 
inclusion of subcategories of types of waters, either alone or in 
combination with similarly situated waters, that can appropriately be 
identified as always lacking or always having a significant nexus. One 
of these alternate approaches in the preamble to the proposed rule was 
to determine by rule that certain additional subcategories of waters 
would be jurisdictional rather than addressed with a case-specific 
basis for determining significant nexus.
    Many commenters expressed support for the agencies' proposed 
approach to case-specific waters, included additional references to 
support these waters being protected by rule, and supported the 
treatment of certain categories of waters as similarly situated (that 
is, evaluating them in combination with similarly situated waters for 
the purposes of the significant nexus analysis). Some suggested the 
agencies establish jurisdiction over case-specific waters by rule and 
provided detailed information in support of their position. Other 
commenters suggested additional subcategories of waters be considered 
as jurisdictional or as similarly situated by rule, such as playa 
lakes, kettle lakes, and woodland vernal pools.
    However, there was a concern raised by other commenters about what 
was termed regulatory overreach and uncertainty created by the ``other 
waters'' category in the proposal. Some commenters stated that the 
``other waters'' category in the proposal would allow the agencies to 
regulate virtually any water. To address this concern, the rule places 
limits on which waters could be subject to a case-specific significant 
nexus determination, in recognition that case-specific analysis of 
significant nexus is resource-intensive and based on the body of 
science that exists. As noted above, the agencies also establish by 
rule subcategories of waters that are ``similarly situated'' for the 
purposes of a significant nexus analysis because science supports that 
the subcategory waters fall within a higher gradient of connectivity. 
By not determining that any one of the waters available for case-
specific analysis is jurisdictional by rule, the agencies are 
recognizing the gradient of connectivity that exists and will assert 
jurisdiction only when that connection and the downstream effects are 
significant and more than speculative and insubstantial.
    Waters are covered under the rule only where they are identified as 
jurisdictional in paragraphs (a)(1) through (a)(6), where they are not 
excluded under paragraph (b), or where they are within the limited 
number of subcategories listed in paragraphs (a)(7) and (a)(8) and have 
a case-specific significant nexus to a traditional navigable water, 
interstate water, or the territorial seas. These limits on jurisdiction 
reflect the case law and are in response to comments requesting greater 
regulatory certainty. Although some commenters suggested additional 
subcategories of waters for consideration, such as playa lakes and 
kettle lakes, the agencies at this time are not able to determine that 
the available science supports that the suggested additional 
subcategories of waters as a class have a significant nexus to 
traditional navigable waters, interstate waters, or the territorial 
seas. However, to be clear, under the rule, individual waters of the 
suggested additional subcategories are jurisdictional where they meet 
the requirements of paragraphs (a)(1) through (a)(6) or (a)(8) (e.g., a 
playa lake that is an interstate water, a kettle lake that is an 
adjacent water, or a woodland vernal pool that is less than 4,000 feet 
from a jurisdictional tributary and is determined on a case-specific 
basis to have a significant nexus to a traditional navigable water, 
interstate water, or the territorial seas).
    In consideration of the variety of views of the commenters, the 
Science Report, the input from the SAB, and the developing state of the 
science, the agencies reasonably decided not to establish jurisdiction 
over all waters that do not meet the requirements of paragraph (a)(1) 
through (a)(6) by rule. Instead, the agencies established case-specific 
provisions for some specified waters at paragraph (a)(7) and waters 
within the boundaries at paragraph (a)(8). This approach strikes a 
balance between requests for clear boundaries and limited case-specific 
reviews with scientific support.

I. Waters and Features That Are Not ``Waters of the United States''

    In the rule, the agencies identify a variety of waters and features 
that are not ``waters of the United States.'' Prior converted cropland 
and waste treatment systems have been excluded from this definition 
since 1992 and 1979, respectively, and they remain substantively and 
operationally unchanged. Only ministerial changes to delete an outdated 
cross reference are made to the exclusion for waste treatment systems. 
The agencies add exclusions for all waters and features identified as 
generally exempt in preamble language from Federal Register documents 
by the Corps on November 13, 1986, and by EPA on June 6, 1988. This is 
the first time these exclusions have been established by rule. In 
addition, under prior preamble language, the agencies retained the 
authority to determine that a particular feature generally considered 
non-jurisdictional was in fact a ``water of the United States.'' The 
agencies do not retain that authority for features excluded under the 
rule. The agencies for the first time also establish by rule that 
certain ditches are excluded from jurisdiction. The agencies add 
exclusions for groundwater and erosional features, as well as 
exclusions for some waters that were identified in public comments as 
possibly being found jurisdictional under proposed rule language where 
this was never the agencies' intent. These exclusions are reflective of 
current agencies' practice, and their inclusion in the rule furthers 
the agencies' goal of providing greater clarity over what waters are 
and are not protected under the CWA. Importantly, under the rule all 
waters and features identified in paragraph (b) as excluded will not be 
``waters of the United States,'' even if they otherwise fall within one 
of the categories in paragraphs (a)(4) through (a)(8). For example, a 
ditch that is excluded under paragraph (b)(3)(i) or (b)(3)(ii) is not 
jurisdictional even when the ditch connects directly or through another 
water to a traditional navigable water, interstate water, or the 
territorial seas. The proposed rule referenced paragraphs (a)(1) 
through (a)(8), but the agencies did not intend to exclude any 
traditional navigable waters, for example, and the revision clarifies 
that. Finally, nothing in the rule is intended to change the way in 
which the Corps applies individual or nationwide permits.
    The exclusions reflect the agencies' long-standing practice and 
technical judgment that certain waters and

[[Page 37097]]

features are not subject to the CWA. The exclusions are also guided by 
Supreme Court cases. The significant nexus standard arises from the 
case law and is used to interpret the terms of the CWA. Thus, a 
significant nexus determination is not a purely scientific inquiry, but 
rather is a determination by the agencies in light of the statutory 
language, the statute's goals, objectives and policies, the case law, 
the relevant science, and the agencies' technical expertise and 
experience. The plurality opinion in Rapanos also noted that there were 
certain features that were not primarily the focus of the CWA. See 547 
U.S. at 734. In this section of the proposed rule, the agencies are 
drawing lines and concluding that certain waters and features are not 
subject to the jurisdiction of the Clean Water Act. The Supreme Court 
has recognized that clarifying the lines of jurisdiction is a difficult 
task: ``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.'' Riverside Bayview at 132-33. The exclusions are 
an important aspect of the agencies' policy goal of providing clarity 
and certainty. Just as the categorical assertions of jurisdiction over 
covered tributaries and covered adjacent waters simplify the 
jurisdiction issue, the categorical exclusions will likewise simplify 
the process, and they reflect the agencies' determinations of the lines 
of jurisdiction based on science, the case law and the agencies' 
experience and expertise.
    The existing exclusion for waste treatment systems moves to 
paragraph (b)(1) with no substantive changes. One ministerial change is 
the deletion of a cross-reference in the current language to an EPA 
regulation that no longer exists. Because the agencies are not 
addressing the substance of the exclusion, the agencies do not make 
conforming changes to ensure that each of the existing definitions of 
the ``waters of the United States'' for the various CWA programs have 
the exact same language with respect to the waste treatment system 
exclusion, with the exception of deleting the cross-reference.
    Many commenters expressed concern about whether the agencies' 
insertion of a comma following this ministerial change unintentionally 
narrowed the exclusion such that all excluded waste treatment systems 
must be designed to meet the requirements of the Clean Water Act. The 
commenters indicated concerns that waste treatment systems built before 
the Clean Water Act or primarily for purposes of other environmental 
laws could not be exempt. The agencies do not intend to change how the 
waste treatment exclusion is implemented and have deleted this proposed 
comma. Continuing current practice, any waste treatment system built in 
a ``water of the United States'' would need a section 404 permit to be 
constructed and a section 402 permit for discharges from the waste 
treatment system into ``waters of United States.''
    A number of commenters suggested the agencies clarify how the waste 
treatment system exclusion is currently implemented. Many comments 
raised questions about stormwater systems and wastewater reuse and 
whether such facilities qualified under the waste treatment system 
exclusion as part of a complete waste treatment system. For clarity, 
the agencies have identified related exclusions in paragraphs (b)(6) 
and (b)(7). Many commenters also suggested making substantive changes 
to the existing exclusion for waste treatment systems. Because the 
agencies are not making any substantive changes to the waste treatment 
system exclusion and these comments are outside the scope of the 
proposed rule, the final rule does not reflect changes suggested in 
public comments.
    The existing exclusion for prior converted cropland moves to 
paragraph (b)(2) of the rule and is unchanged. A number of commenters 
suggested changes to the existing exclusion for prior converted 
cropland. As with waste treatment systems, the preamble to the proposed 
rule stated this rulemaking was not making changes to the exclusion for 
prior converted cropland. As a result, comments requesting changes to 
the prior converted cropland exclusion or seeking clarification of how 
the exclusion is implemented in the field are outside the scope of this 
rulemaking, and the rule does not reflect changes or respond to issues 
raised in public comments. The agencies will continue to implement this 
exclusion consistent with current policy and practice.
    The agencies identify excluded ditches in paragraph (b)(3). 
Jurisdictional ditches are discussed at more detail in section IV.F. 
The rule excludes all ditches with ephemeral flow that are not 
excavated in or relocate a tributary. The rule also excludes ditches 
with intermittent flow that are not a relocated tributary, excavated in 
a tributary, or drain wetlands, regardless of whether or not the 
wetland is a jurisdictional water. Finally, ditches that do not connect 
to a traditional navigable water, interstate water, or territorial sea 
either directly or through another water are excluded, regardless of 
whether the flow is ephemeral, intermittent, or perennial. These ditch 
exclusions are clearer for the regulated public to identify and more 
straightforward for agency staff to implement than the proposed rule or 
current policies. The ditch exclusions do not affect the possible 
status of a ditch as a point source.
    Many comments addressed ditches, and many of these comments are 
reflected in the approach to ditches articulated in the rule. The 
majority of commenters requested that the agencies' ditch exclusion be 
clarified or broadened. Many commenters were confused by the term 
``uplands'' and did not feel the term had a common understanding. For 
example, some commenters felt the term referred only to areas at higher 
elevations in the landscape. Many expressed concerns that all ditches 
would be jurisdictional under the proposed rule. Many groups especially 
called for exclusions of roadside ditches.
    The revised exclusions reflect the agencies' careful consideration 
of these comments. First, the agencies have eliminated the term 
``uplands'' in response to the questions the term created. Second, the 
agencies have instead provided a clearer statement of the types of 
ditches that are subject to exclusion--ditches that are not excavated 
in or relocate a tributary and ditches that do not drain a wetland. 
Eliminating the term ``uplands'' with this more straightforward 
description should improve clarity. Finally, the agencies have more 
clearly stated the flow regimes in ditches that are subject to the 
exclusions; these flow regimes are described earlier and have been used 
by the agencies consistently and are readily understood by field staff 
and the public.
    As noted, the agencies received many comments asking that roadside 
ditches be addressed, and more specifically excluded, in the final 
rule. Like the proposed rule, the final rule does not include an 
explicit exclusion for roadside ditches, but the agencies believe the 
exclusions included in the final rule will address the vast majority of 
roadside and other transportation ditches. Moreover, since the agencies 
have focused in the final rule on the physical characteristics of 
excluded ditches, the exclusions will address all ditches that the 
agencies have

[[Page 37098]]

concluded should not be subject to jurisdiction, including certain 
ditches on agricultural lands and ditches associated with modes of 
transportation, such as roadways, airports, and rail lines.
    As discussed in Section IV.F.1., the definition of tributary 
includes natural, undisturbed waters and those that have been man-
altered or constructed, but which science shows function as a 
tributary. In addition, natural streams and rivers that are altered or 
modified for purposes as flood control, erosion control, and other 
reasons does not convert the tributary to a ditch. A stream or river 
that has been channelized or straightened because its natural sinuosity 
has been altered, cutting off the meanders, is not a ditch. A stream 
that has banks stabilized through use of concrete or rip-rap (e.g., 
rocks or stones) is not a ditch. The Los Angeles River, for example, is 
a ``water of the United States'' (and, indeed, a traditional navigable 
water) and remains a ``water of the United States'' and is not a 
excluded under paragraph (b)(3), even where it has been ditched, 
channelized, or concreted.
    The rule excludes ditches with ephemeral flow except where a ditch 
is excavated in or relocates a covered tributary. Under the rule, that 
portion of a ditch with ephemeral flow actually excavated in or 
relocating the covered tributary would be considered jurisdictional. 
The jurisdictional status of upstream and downstream portions of the 
same ditch would have to be assessed based on the specific facts and 
under the terms of the rule to determine flow characteristics and 
whether or not the ditch is excavated in or relocates a tributary. This 
approach reasonably balances the exclusion with the need to ensure that 
covered tributaries, and the significant functions they provide, are 
preserved. A ditch that relocates a stream is not an excluded ditch 
under paragraph (b)(3), and a stream is relocated either when at least 
a portion of its original channel has been physically moved, or when 
the majority of its flow has been redirected. A ditch that is a 
relocated stream is distinguishable from a ditch that withdraws water 
from a stream without changing the stream's aquatic character. The 
latter type of ditch is excluded from jurisdiction where it meets the 
listed characteristics of excluded ditches under paragraph (b)(3). The 
agencies will determine historical presence of tributaries using a 
variety of resources, such as USGS and state and local maps, historic 
aerial photographs, local surface water management plans, street 
maintenance data, wetlands and conservation programs and plans, as well 
as functional assessments and monitoring efforts.
    The rule also excludes ditches with intermittent flow except where 
a ditch is excavated in or relocates a covered tributary, or drains 
wetlands. Where an excluded ditch drains a wetland, the segment of the 
ditch that physically intersects the wetland would be considered 
jurisdictional. The jurisdictional status of upstream and downstream 
portions of the same ditch would have to be assessed based on the 
specific facts and under the terms of the rule to determine flow 
characteristics and whether or not the ditch drains a wetland. The 
provision of paragraph (b)(3) addressing draining of wetlands is 
specific to ditches with intermittent flow. As discussed previously, 
features that are ephemeral will flow only in response to precipitation 
events, such as rainfall or snowmelt. Ditches with ephemeral flow, 
therefore, do not typically have the flow characteristics 
characteristic of ditches that drain wetlands. The agencies have 
accordingly focused on intermittent ditches that drain wetlands.
    In addition, the agencies clarify that a ditch drains a wetland 
when it physically intersects the wetland. If the ditch has been cut to 
carry only ephemeral flows, such as those following a storm event, the 
effect of the ditch is minimal as it carries only that flow that 
overtops the wetland during and immediately following the rain event. 
However, if the ditch has been cut to carry intermittent or perennial 
flows from the wetland, the ditch is serving as a conduit for 
transferring flow from the wetland to a downstream tributary. As a 
result of the cut ditch, the wetland's hydrologic regime is modified 
and can generally affect the natural functions performed by the 
wetland. When the ditch has been cut to carry intermittent or perennial 
flow from the wetland to the downstream tributary, the wetland soils 
and vegetation can shift into a community that supports less hydric 
soils and a mix of riparian or upland vegetation. Consequently, the 
ditch is draining the wetland and the wetland quality degrades and may 
cease to exist over time. Therefore, a ditch that carries intermittent 
flow and physically intersects with a wetland is not excluded under 
this provision.
    A number of commenters expressed concern that a ditch could be 
viewed as both a point source and a ``water of the United States.'' 
However, the approach that ditches can be considered both reflects the 
CWA itself as well as longstanding agency policy.
    Paragraph (b)(4) of the rule identifies features and waters that 
the agencies have identified as generally not ``waters of the United 
States'' in previous preambles or guidance documents. Codifying these 
longstanding practices supports the agencies' goals of providing 
greater clarity, certainty, and predictability for the regulated public 
and the regulators. The agencies' 1986 and 1988 preambles indicated 
that these waters could be determined on a case-specific basis to be 
``waters of the United States.'' This rule does not allow for this 
case-specific analysis to be used to establish jurisdiction--these 
waters are categorically excluded from jurisdiction. Some of the 
exclusions have been modified slightly to address public comments and 
improve clarity. The following features are not ``waters of the United 
States'':
     Artificially irrigated areas that would revert to dry land 
should application of irrigation water to that area cease
     Artificial, constructed lakes or ponds created by 
excavating and/or diking dry land such as farm and stock watering 
ponds, irrigation ponds, settling basins, log cleaning ponds, cooling 
ponds, or fields flooded for rice growing
     Artificial reflecting pools or swimming pools created by 
excavating and/or diking dry land
     Small ornamental waters created by excavating and/or 
diking dry land for primarily aesthetic reasons
     Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand or gravel that fill with water
     Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways
     Puddles
    Several of these exclusions use the phrase ``dry land.'' This 
phrase appears in the 1986 and 1988 preambles, and the agencies believe 
the term is well understood based on the more than 30 years of practice 
and implementation. But in keeping with the goal of providing greater 
clarity, the agencies state that ``dry land'' refers to areas of the 
geographic landscape that are not water features such as streams, 
rivers, wetlands, lakes, ponds and the like. However, it is important 
to note that a ``water of the United States'' is not considered ``dry 
land'' just because it lacks water at a given time. Similarly, an area 
remains ``dry land'' even if it is wet after a rainfall event. The 
agencies received comments suggesting that the

[[Page 37099]]

final rule provide a definition of ``dry land'' as it relates to the 
exclusion for stormwater control features. The agencies considered the 
request and determined that there was no agreed upon definition given 
geographic and regional variability. The agencies concluded that 
further clarity on this issue can be provided during implementation.
    In the exclusion for artificial lakes or ponds, the agencies have 
removed language regarding ``use'' of the ponds, including the term 
``exclusively.'' In most cases, the ``use'' of the pond is captured in 
its name. More importantly, the agencies recognize that artificial 
lakes and ponds are often used for more than one purpose and can have 
other beneficial purposes, such as animal habitat, water retention or 
recreation. For example, rice growing is typically facilitated by land 
leveling and inundation that floods vast areas. The fields are flooded 
for the purpose of weed control and to facilitate rice cultivation, but 
these rice fields are often extensively used by waterfowl and other 
wildlife. The agencies agree with commenters who raised concern that 
rice fields ``used'' both for rice growing and waterfowl habitat should 
continue to be excluded even where they are not used ``exclusively'' 
for a single purpose. The change to the exclusion reflects the 
agencies' practice and ensures that waters the agencies have 
historically not treated as jurisdictional do not become so because of 
another incidental beneficial use.
    The agencies have also added farm ponds, log cleaning ponds, and 
cooling ponds to the list of excluded ponds in the rule based on public 
comments. The list of ponds has always been illustrative rather than 
exhaustive, and the additions respond to requests to clarify that farm 
ponds, and log cleaning ponds \12\ created in dry land are excluded. 
The agencies have also added cooling ponds created in dry land to the 
list of excluded waters. The agencies also note that cooling ponds that 
are created under section 404 in jurisdictional waters and that have 
NPDES permits are subject to the waste treatment system exclusion, 
which is not changing. Cooling ponds created to serve as part of a 
cooling water system with a valid state permit constructed in waters of 
the United States prior to enactment of the Clean Water Act and 
currently excluded from jurisdiction remain excluded under the new 
rule. Additional ponds will also likely fall under the exclusion based 
on site specific evaluation, including, for example, fire control ponds 
and fishing ponds excavated from dry land. Artificial lakes and ponds 
created in dry land that do not connect to jurisdictional waters are 
covered by this exclusion. Where these ponds do connect and discharge 
to jurisdictional waters, the agencies will evaluate factors such as 
the potential for introduction of pollutants and coverage under an 
issued NPDES permit. As a general matter, ponds created in dry land 
that discharge to ``waters of the United States'' are covered by the 
exclusion where such discharge is regulated under a NPDES permit. 
Conveyances created in dry land that are physically connected to and 
are a part of the excluded feature are also excluded. These artificial 
features are working together as a system, and it is appropriate to 
treat them as one functional unit. The agencies emphasize that ponds 
excluded from ``waters of the United States'' can, in some 
circumstances, be point sources of pollution subject to section 301 of 
the Act.
---------------------------------------------------------------------------

    \12\ Log cleaning ponds are used to float logs for removal of 
twigs, branches, and large knots.
---------------------------------------------------------------------------

    The rule includes several refinements to the exclusion for water-
filled depressions created as a result of certain activities. In 
addition to construction activity, the agencies have also excluded 
water-filled depressions created in dry land incidental to mining 
activity. This change is consistent with the agencies' 1986 and 1988 
preambles, which generally excluded pits excavated for obtaining fill, 
sand or gravel, and there is no need to distinguish between features 
based on whether they are created by construction or mining activity.
    The agencies also here clarify their longstanding view that only 
the specific land being directly irrigated that would revert to dry 
land should irrigation cease is exempt; it is not the case that all 
waters within watersheds where irrigation occurs are exempt.
    The rule identifies all erosional features, including gullies and 
rills, as non-jurisdictional features. While the proposed rule 
specifically identified gullies and rills, the agencies intended that 
all erosional features would be excluded. The final rule makes this 
clear. Erosional features are not jurisdictional under the terms of 
paragraph (a) and the definitions in paragraph (c), especially the 
definition of tributary. These features are specifically excluded in 
the rule to avoid confusion, because preceding guidance identified them 
as non-jurisdictional and many commenters stated these exclusions were 
important to maintain in the rule.
    Tributaries can be distinguished from erosional features by the 
presence of bed and banks and an ordinary high water mark. Concentrated 
surface runoff can occur within erosional features without creating the 
permanent physical characteristics associated with bed and banks and 
ordinary high water mark. See Technical Support Document. It should be 
noted that some ephemeral streams are colloquially called ``gullies'' 
or the like even when they exhibit a bed and banks and an ordinary high 
water mark; regardless of the name they are given locally, waters that 
meet the definition of tributary are not excluded erosional features.
    The rule also excludes lawfully constructed grassed waterways. 
Grassed waterways are lawfully constructed for purposes of this rule 
either where they are on dry land and replace non-jurisdictional 
erosional features or, more commonly, where they have been lawfully 
converted from an intermittent or ephemeral stream under a CWA permit. 
Once converted to grassed waterways, these former streams segments no 
longer exhibit a bed and banks or ordinary high water mark and are 
excluded because they do not meet the definition of ``tributary.'' 
However, such conversion does not sever jurisdiction over the entire 
length of the tributary above and below the grassed waterway. Instead, 
the grassed waterway is considered a constructed break in the bed and 
banks and ordinary high water mark. This is reflected in the definition 
of tributary, which specifically addresses natural or man-made breaks 
in bed and banks and ordinary high water mark.
    The final rule adds an exclusion for puddles. The proposed rule did 
not explicitly exclude puddles because the agencies have never 
considered puddles to meet the minimum standard for being a ``water of 
the United States,'' and it is an inexact term. A puddle is commonly 
considered a very small, shallow, and highly transitory pool of water 
that forms on pavement or uplands during or immediately after a 
rainstorm or similar precipitation event. However, numerous commenters 
asked that the agencies expressly exclude them in a rule. The final 
rule does so.
    The agencies include an exclusion for groundwater, including 
groundwater drained through subsurface drainage systems. As discussed 
in the preamble to the proposed rule, the agencies have never 
interpreted ``waters of the United States'' to include groundwater. The 
exclusion does not apply to surface expressions of groundwater, as some 
commenters requested, such as where groundwater emerges on the surface 
and

[[Page 37100]]

becomes baseflow in streams or spring fed ponds.
    The final rule includes a new exclusion in paragraph (b)(6) for 
stormwater control features constructed to convey, treat, or store 
stormwater that are created in dry land. The agencies stated in the 
proposed rule that the exclusions were guided by decisions of the 
Supreme Court and were intended to further the agencies' goal of 
providing clarity and certainty. The agencies in the proposed rule 
sought to provide a ``full description'' of the waters that will not be 
``waters of the United States.'' 79 FR at 22218. In response to the 
agencies' proposal, several commenters indicated additional clarity was 
needed, particularly with respect to stormwater control features and 
wastewater recycling facilities. This exclusion responds to numerous 
commenters who raised concerns that the proposed rule would adversely 
affect municipalities' ability to operate and maintain their stormwater 
systems, and also to address confusion about the state of practice 
regarding jurisdiction of these features at the time the rule was 
proposed.
    The agencies' longstanding practice is to view stormwater control 
measures that are not built in ``waters of the United States'' as non-
jurisdictional. Conversely, the agencies view some waters, such as 
channelized or piped streams, as jurisdictional currently even where 
used as part of a stormwater management system. Nothing in the proposed 
rule was intended to change that practice. Nonetheless, the agencies 
recognize that the proposed rule brought to light confusion about which 
stormwater control features are jurisdictional waters and which are 
not, and agree that it is appropriate to address this confusion by 
creating a specific exclusion in the final rule for stormwater controls 
features that are created in dry land.
    Many commenters, particularly municipalities and other public 
entities that operate storm sewer systems and stormwater management 
programs, expressed concern that various stormwater control measures--
such as stormwater treatment systems, rain gardens, low impact 
development/green infrastructure, and flood control systems--could be 
considered ``waters of the United States'' under the proposed rule, 
either as part of a tributary system, an adjacent water, or as a result 
of a case-specific significant nexus analysis. This exclusion should 
clarify the appropriate limits of jurisdiction relating to these 
systems. A key element of the exclusion is whether the feature or 
control system was built in dry land and whether it conveys, treats, or 
stores stormwater. Certain features, such as curbs and gutters, may be 
features of stormwater collection systems, but have never been 
considered ``waters of the United States.''
    Stormwater control features have evolved considerably over the past 
several years, and their nomenclature is not consistent, so in order to 
avoid unintentionally limiting the exclusion, the agencies have not 
included a list of excluded features in the rule. The rule is intended 
to exclude the diverse range of control features that are currently in 
place and may be developed in the future.
    Traditionally, stormwater controls were designed to direct runoff 
away from people and property as quickly as possible. Cities built 
systems to collect, convey, or store stormwater, using structures such 
as curbs, gutters, and sewers. Often, cities used existing stream 
networks as part of the stormwater drainage network. Retention and 
detention stormwater ponds were built to store excess stormwater until 
it could be more safely released.
    Recently, treatment of stormwater has become more prevalent to 
remove harmful pollutants before the stormwater is discharged. Even 
more recently, cities have turned to green infrastructure, using 
existing natural features or creating new features that mimic natural 
hydrological processes that work to infiltrate or evapo-transpirate 
precipitation, to manage stormwater at its source and keep it out of 
the conveyance system. These engineered components of stormwater 
management systems can address both water quantity and quality 
concerns, as well as provide other benefits to communities. This rule 
is designed to avoid disincentives to this environmentally beneficial 
trend in stormwater management practices. This exclusion does not cover 
transportation ditches; those ditches are addressed under paragraph 
(b)(3) of the rule. As discussed above, the exclusion in paragraph 
(b)(6) is intended to address engineered stormwater control structures 
in municipal or urban environments. Stormwater control features are 
designed to address runoff that occurs during and shortly after 
precipitation events; as a result, stormwater features that convey 
runoff are expected to only carry ephemeral or intermittent flow. For 
ease of implementation, the agencies want water features to be dealt 
with under only one provision of the rule. However, the agencies do not 
expect the scope of ditches excluded to be different under paragraphs 
(b)(3) and (b)(6), so there should be little practical need to 
distinguish between the two.
    Paragraph (b)(7) of the rule clarifies that wastewater recycling 
structures constructed in dry land are excluded. This new exclusion 
clarifies the agencies' current practice that such waters and water 
features used for water reuse and recycling are not jurisdictional when 
constructed in dry land. The agencies recognize the importance of water 
reuse and recycling, particularly in areas like California and the 
Southwest where water supplies can be limited and droughts can 
exacerbate supply issues. This exclusion responds to numerous 
commenters and encourages water reuse and conservation while still 
appropriately protecting the chemical, physical, and biological 
integrity of the nation's water under CWA.
    The agencies specifically exclude constructed detention and 
retention basins created in dry land used for wastewater recycling as 
well as groundwater recharge basins and percolation ponds built for 
wastewater recycling. Many commenters noted the growing interest in and 
commitment to water recycling and reuse projects. Detention and 
retention basins can play an important role in capturing and storing 
water prior to beneficial reuse. Similarly, groundwater recharge basins 
and percolation ponds are becoming more prevalent tools for water reuse 
and recycling. These features are used to collect and store water, 
which then infiltrates into groundwater via permeable soils. Though 
these features are often created in dry land, they are also often 
located in close proximity to tributaries or other larger bodies of 
water. The exclusion also covers water distributary structures that are 
built in dry land for water recycling. These features often connect or 
carry flow to other water recycling structures, for example a channel 
or canal that carries water to a percolation pond. The agencies have 
not considered these water distributary systems jurisdictional where 
they do not have surface connections back into, and contribute flow to, 
``waters of the United States.'' In contrast, the agencies have 
consistently regulated aqueducts and canals as ``waters of the United 
States'' where they serve as tributaries, removing water from one part 
of the tributary network and moving it to another. The exclusion in 
paragraph (b)(7) codifies long-standing agency practice and encourages 
water management practices that the agencies agree are important and 
beneficial.
    The agencies also received other suggestions for new exclusions 
that

[[Page 37101]]

were not adopted in the final rule. The agencies determined that it was 
not appropriate or necessary to add certain requested exclusions for 
one or more reasons, including: (1) The requested exclusion was so 
broadly characterized as to introduce significant confusion and 
potentially have the effect of excluding waters that the agencies have 
consistently determined should be covered as ``waters of the U.S.,'' 
(2) the requested exclusion was so site-specific or activity-based as 
to lack illustrative value, or (3) the requested exclusion was likely 
covered by another exclusion in the final rule.
    It is important to note that while the waters listed in the 
exclusions are not ``waters of the United States,'' they can serve as a 
hydrologic connection that the agencies would consider under a case-
specific significant nexus under paragraphs (a)(7) and (a)(8). For 
example, a wetland may be directly hydrologically connected to a 
covered tributary via flow through an excluded non-wetland swale. While 
the swale itself is excluded from jurisdiction, the connection of the 
wetland to the tributary is relevant for determining whether the 
wetland has a significant nexus to downstream traditional navigable 
waters, interstate waters, or the territorial seas. In addition, these 
geographic features may function as ``point sources'' under CWA section 
502(14), such that discharges of pollutants to waters through these 
features would be subject to other CWA regulations (e.g., CWA section 
402).

V. Economic Impacts

    This rule establishing the definition of ``waters of the United 
States,'' by itself, imposes no direct costs. The potential costs and 
benefits incurred as a result of this rule are considered indirect, 
because the rule involves a definitional change to a term that is used 
in the implementation of CWA programs (i.e., sections 303, 305, 311, 
401, 402, and 404). Entities currently are, and will continue to be, 
regulated under these programs that protect ``waters of the United 
States'' from pollution and destruction. Each of these programs may 
subsequently impose direct or indirect costs as a result of 
implementation of their specific regulations.
    While the rule imposes no direct costs, the agencies prepared an 
economic analysis for informational purposes. In preparing the economic 
analysis to accompany the final rule, the agencies considered what 
should be the appropriate baseline for comparison. Existing regulations 
and historic practice in implementing them represent one appropriate 
baseline for comparison, and because the final rule is narrower in 
jurisdictional scope than the existing regulations, there would be no 
additional costs in comparison to this baseline. A comparison to recent 
field practice following the 2008 guidance is also an appropriate 
baseline, and the agencies prepared illustrative estimates of how the 
costs and benefits of various CWA programs may change with an increase 
in positive jurisdictional determinations relative to that baseline.
    To estimate changes in potential costs and benefits of different 
CWA programs, the economic analysis utilizes available program data to 
estimate the extent to which assertion of jurisdiction might change 
under the associated final policies. The proposed rule analysis 
utilized CWA Section 404 jurisdictional determination and permit data 
from fiscal years 2009-2010 (post SWANCC and Rapanos), following 
issuance of program guidance in 2008 by the EPA and the Corps. The 
analysis for the final rule has been updated using data from fiscal 
years 2013-2014, providing a comparison to a more recent year of data, 
which responds to public comments. An estimate of how assertion of 
jurisdiction may change compared to the recent practice baseline, 
developed using updated data from fiscal years 2013-2014 jurisdictional 
determinations, is then applied to cost and benefit information for 
affected CWA programs. Additional updates to the economic analysis 
include a refined approach to calculating benefits from section 404 
compensatory mitigation, differentiating between emergent and forested 
wetlands, as well as presenting results in ranges to reflect 
uncertainty. The agencies' economic analysis yielded the following key 
conclusions:
     Compared to the current regulations and historic practice 
of making jurisdictional determinations, the scope of jurisdictional 
waters will decrease, as would the costs and benefits of CWA programs.
     Compared to a baseline of recent practice, the agencies 
assessed two scenarios. Those scenarios result in an estimated increase 
of between 2.84 and 4.65 percent in positive jurisdictional 
determinations annually.
     The agencies' analysis indicates that for both scenarios, 
the change in benefits of CWA programs exceed the costs by a ratio of 
greater than 1:1.
     The economic analysis estimates that incremental annual 
costs for scenario 1 will range from $158M-$307M and incremental annual 
benefits will range from $339M-$350M and, for scenario 2, costs will 
range from $237M-$465M and benefits will range from $555M-$572M.

The agencies conducted this economic analysis to provide the public 
with information on the potential changes to the costs and benefits of 
various CWA programs that may result from a change in the number of 
positive jurisdictional determinations. The economic analysis was done 
for informational purposes only, and the final decisions on the scope 
of ``waters of the United States'' in this rulemaking are not based on 
consideration of the information in the economic analysis. The economic 
analysis fulfills the requirements of Executive Orders 13563 and 12866. 
An explanation of the data, methods, and assumptions used to estimate 
indirect costs and benefits can be found in the Economic Analysis for 
the Clean Water Rule; Definition of ``Waters of the United States'' 
Under the Clean Water Act (Final Rule) in the accompanying docket.

VI. Related Acts of Congress, Executive Orders, and Agency Initiatives

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

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a ``significant regulatory action.'' Accordingly, EPA and the 
Army submitted this action to the Office of Management and Budget (OMB) 
for review under Executive Orders 12866 and 13563 (76 FR 3821, January 
21, 2011) and any changes made in response to OMB recommendations have 
been documented in the docket for this action.
    In addition, EPA and the Army prepared an analysis of the potential 
costs and benefits associated with this action. This analysis is 
contained in Economic Analysis of the EPA-Army Clean Water Rule. A copy 
of the analysis is available in the docket for this action.

B. Paperwork Reduction Act

    This action does not impose any information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Burden is defined at 5 CFR 1320.3(b). An agency may not conduct or 
sponsor, and a person is not required to respond to, a collection of 
information unless it displays a currently valid OMB control number. 
The OMB control numbers for the CWA section 402 program may be found at 
40 CFR 9.1. (OMB Control No. 2040-0004, EPA ICR No. 0229.19). For the 
CWA section 404 regulatory

[[Page 37102]]

program, the current OMB approval number for information requirements 
is maintained by the Corps of Engineers (OMB approval number 0710-
0003). However, there are no new approval or application processes 
required as a result of this rulemaking that necessitate a new 
Information Collection Request (ICR).

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice-and-comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of this final action on small 
entities, ``small entity'' is defined as: (1) A small business that is 
a small industrial entity as defined in the U.S. Small Business 
Administration's size standards (see 13 CFR 121.201); (2) a small 
governmental jurisdiction that is a government of a city, county, town, 
school district, or special district with a population of less than 
50,000; or (3) a small organization that is any not-for-profit 
enterprise that is independently owned and operated and is not dominant 
in its field.
    After considering the economic impacts of this rule on small 
entities, we certify that this final rule will not have a significant 
economic impact on a substantial number of small entities. See, e.g., 
Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855 (D.C. Cir. 2001); 
Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000); Am. Trucking Ass'n v. 
EPA, 175 F.3d 1027 (D.C. Cir. 1999); Mid-Tex Elec. Co-op, Inc. v. FERC, 
773 F.2d 327 (D.C. Cir. 1985).
    Under the RFA, the impact of concern is any significant adverse 
economic impact on small entities, because the primary purpose of the 
initial regulatory flexibility analysis is to identify and address 
regulatory alternatives ``which minimize any significant economic 
impact of the proposed rule on small entities.'' 5 U.S.C. 603. The 
scope of jurisdiction in this rule is narrower than that under the 
existing regulations. See 40 CFR 122.2 (defining ``waters of the United 
States''). Because fewer waters will be subject to the CWA under the 
rule than are subject to regulation under the existing regulations, 
this action will not affect small entities to a greater degree than the 
existing regulations. As a consequence, this action will not have a 
significant adverse economic impact on a substantial number of small 
entities, and therefore no regulatory flexibility analysis is required.
    This rule is not designed to ``subject'' any entities of any size 
to any specific regulatory burden. Rather, it is designed to clarify 
the statutory scope of ``the waters of the United States, including the 
territorial seas,'' section 502(7), consistent with Supreme Court 
precedent. This question of CWA jurisdiction is informed by the tools 
of statutory construction and the geographical and hydrological factors 
identified in Rapanos v. United States, 547 U.S. 715 (2006), which are 
not factors readily informed by the RFA.
    Nevertheless, the scope of the term ``waters of the United States'' 
is a question that has continued to generate substantial interest, 
particularly within the small business community, because permits must 
be obtained for many discharges of pollutants into those waters. In 
light of this interest, the EPA and the Army determined to seek wide 
input from representatives of small entities while formulating the 
proposed and final definition of this term that reflects the intent of 
Congress consistent with the mandate of the Supreme Court's decisions. 
Such outreach, although voluntary, is also consistent with the 
President's January 18, 2011 Memorandum on Regulatory Flexibility, 
Small Business, and Job Creation, which emphasizes the important role 
small businesses play in the American economy. This process has enabled 
the agencies to hear directly from these representatives, throughout 
the rule development, about how they should approach this complex 
question of statutory interpretation, together with related issues that 
such representatives of small entities may identify for possible 
consideration in separate proceedings. The agencies have prepared a 
report summarizing their small entity outreach, the results of this 
outreach, and how these results have informed the development of this 
rule. This report, Report of the Discretionary Small Entity Outreach 
for the Revised Definition of Waters of the United States (Docket Id. 
No. EPA-HQ-OW-2011-0880-1927), is available in the docket.

D. Unfunded Mandates Reform Act

    This action does not contain any unfunded mandate under the 
regulatory provisions of Title II of the Unfunded Mandates Reform Act 
of 1995 (UMRA) (2 U.S.C. 1531-1538), and does not significantly or 
uniquely affect small governments. The action imposes no enforceable 
duty on any state, local, or tribal governments, or the private sector, 
and does not contain regulatory requirements that might significantly 
or uniquely affect small governments. The definition of ``waters of the 
United States'' applies broadly to CWA programs.

E. Executive Order 13132: Federalism

    This rule does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.
    Keeping with the spirit of Executive Order 13132 and consistent 
with the agencies' policy to promote communications with state and 
local governments, the agencies consulted with state and local 
officials throughout the process and solicited their comments on the 
proposed action and on the development of the rule.
    For this rule state and local governments were consulted at the 
onset of rule development in 2011, and following the publication of the 
proposed rule in 2014. In addition to engaging key organizations under 
federalism, the agencies sought feedback on this rule from a broad 
audience of stakeholders through extensive outreach to numerous state 
and local government organizations.
    Early in the rulemaking process, EPA held two in-person meetings 
and two phone calls in the fall and winter of 2011. Organizations 
involved include the National Governors Association, the National 
Conference of State Legislatures, the Council of State Governments, the 
National Association of Counties, the National League of Cities, the 
U.S. Conference of Mayors, the County Executives of America, the 
National Associations of Towns and Townships, the International City/
County Management Association, and the Environmental Council of the 
States. Additionally, the National Association of Clean Water Agencies 
and the Association of Clean Water Administrators were invited to 
participate. The agencies held many additional calls and meetings with 
state and local governments and their associations, in preparation for 
the development of a proposed rule.
    Similarly to the outreach conducted prior to the development of the 
rule, the agencies committed themselves to providing a transparent, 
comprehensive, and effective process for taking public comment on the 
proposed rule. As part of this consultation, EPA held a meeting on May 
13, 2014 to seek technical input on the proposed rule from the largest

[[Page 37103]]

national representative organizations for State and local governments. 
During this process the agencies also extended its focused outreach to 
include a series of meetings with the Local Government Advisory 
Committee, and the Environmental Council of the States in conjunction 
with the Association of Clean Water Administrators and the Association 
of State Wetland Managers. In addition to engaging these key 
organizations, the agencies sought additional feedback on the proposed 
rule through broader public outreach to state and local government 
organizations during the public comment period.
    During the consultation process, some participants expressed 
concern that the proposed changes may impose a resource burden on state 
and local governments. Some participants urged EPA to ensure that 
states are not unduly burdened by the regulatory revisions.
    The agencies have prepared a report summarizing their voluntary 
consultation and extensive outreach to State, local, and county 
governments, the results of this outreach, and how these results have 
informed the development of today's rule. This report, Report on the 
Discretionary Consultation and Outreach to State, Local, and County 
Governments on the Clean Water Rule: Definition of ``Waters of the 
United States;'' Final Rule (Docket Id. No. EPA-HQ-OW-2011-0880) is 
available in the docket for this rule.

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

    Subject to the Executive Order (E.O.) 13175 (65 FR 67249, November 
9, 2000), agencies generally may not issue a regulation that has tribal 
implications, (1) that imposes substantial direct compliance costs, and 
that is not required by statute, unless the Federal government provides 
the funds necessary to pay the direct compliance costs incurred by 
tribal governments, or the agencies consult with tribal officials early 
in the process of developing the proposed regulation and develop a 
tribal summary impact statement, or (2) that preempts tribal law unless 
the agencies consult with tribal officials early in the process of 
developing the proposed regulation and develops a tribal summary impact 
statement.
    This action does not have tribal implications as specified in E.O. 
13175. In compliance with the EPA Policy on Consultation and 
Coordination with Indian Tribes (May 4, 2011), the agencies consulted 
with tribal officials throughout the rulemaking process to gain an 
understanding of tribal views and solicited their comments on the 
proposed action and on the development of this rule. In the course of 
this consultation, EPA and the Corps jointly participated in aspects of 
the process.
    The agencies began consultation with federally-recognized Indian 
tribes on the Clean Water Rule defining ``waters of the United States'' 
in October 2011. The consultation and coordination process, including 
providing information on the development of an accompanying science 
report on the connectivity of streams and wetlands, continued, in 
stages, over a four year period, until the close of the public comment 
period on November 14, 2014. EPA invited tribes to provide written 
input on the rulemaking throughout both the tribal consultation process 
and public comment period.
    EPA specifically consulted with tribal officials to gain an 
understanding of, and to address, the tribal views on the proposed 
rule. In 2011, close to 200 tribal representatives and more than 40 
tribes participated in the consultation process, which included 
multiple webinars and national teleconferences and face-to-face 
meetings. In addition, EPA received written comments from three tribes 
during the initial consultation period.
    EPA continued to provide status updates to the National Tribal 
Water Council and the National Tribal Caucus during 2012 through 2014. 
The final consultation event was completed on October 23, 2014 as a 
national teleconference with the Office of Water's Deputy Assistant 
Administrator. Ultimately, EPA received an additional 23 letters from 
tribes/tribal organizations by the completion of the consultation 
period. The comments indicated that Tribes, overall, support increased 
clarity of waters protected by the Clean Water Act, but some expressed 
concern with the consultation process and the burden of any expanded 
jurisdiction. The agencies considered the feedback received through 
consultation and written comments in developing today's rule.
    The agencies have prepared a report summarizing their consultation 
with tribal nations, and how these results have informed the 
development of this rule. This report, Final Summary of Tribal 
Consultation for the Clean Water Rule: Definition of ``Waters of the 
United States'' Under the Clean Water Act; Final Rule (Docket Id. No. 
EPA-HQ-OW-2011-0880), is available in the docket for this rule.

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

    This action is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because the environmental health or safety risks 
addressed by this action do not present a disproportionate risk to 
children.

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

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs federal agencies to use voluntary consensus standards in 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. NTTAA directs federal 
agencies to provide Congress, through OMB, explanations when the agency 
decides not to use available and applicable voluntary consensus 
standards.
    This rule does not involve technical standards. Therefore, the 
agencies are not considering the use of any voluntary consensus 
standards.

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

    Executive Order (E.O.) 12898 (59 FR 7629, Feb. 16, 1994) 
establishes Federal executive policy on environmental justice. Its main 
provision directs Federal agencies, to the greatest extent practicable 
and permitted by law, to make environmental justice part of their 
mission by identifying and addressing, as appropriate, 
disproportionately high and adverse human health or environmental 
effects of their programs, policies, and activities on minority 
populations and low-income populations in the United States.
    The agencies have determined that the rule will not have 
disproportionately high and adverse

[[Page 37104]]

human health or environmental effects on minority or low-income 
populations, because it does not adversely affect the level of 
protection provided to human health or the environment.
    The rule defines the scope of waters protected under the CWA. The 
increased clarity regarding the definition of ``waters of the United 
States'' is intended to benefit all regulators, stakeholders, and 
interested parties. In addition, this rule is national in scope and, 
therefore, is not specific to a particular geographic area.
    In the spirit of E.O. 12898, input from environmental justice 
stakeholders was requested during the rule development process, through 
a series of stakeholder meetings between April and November 2014. On 
May 12, 2014, EPA held a focused teleconference with non-traditional 
stakeholders, including environmental justice and faith-based 
stakeholders, to solicit their individual input on the proposed rule. 
The agencies have used the feedback from public outreach as the source 
of early guidance and recommendations for refining the proposed rule. 
Stakeholder input received during public outreach events in combination 
with the written comments received during the public comment period 
have reshaped each of the definitions included in today's rule, and 
incorporate increased clarity for regulators, stakeholders, and the 
regulated public to assist them in identifying waters as ``waters of 
the United States.''
    The agencies prepared a report summarizing their outreach to the 
environmental justice community, analysis of potential impacts, and how 
these results informed the development of the rule. This report, 
Environmental Justice Report for the Clean Water Rule: Definition of 
``Waters of the United States'' Under the Clean Water Act; Final Rule 
(Docket Id. No. EPA-HQ-OW-2011-0880), is available in the docket for 
this rule.

K. Congressional Review Act

    This action is subject to the Congressional Review Act (CRA), and 
the agencies will submit a rule report to each House of the Congress 
and to the Comptroller General of the United States. This action is a 
``major rule'' as defined by 5 U.S.C. 804(2) based on potential 
indirect costs.

L. Environmental Documentation

    In this joint rulemaking, the agencies establish a definitional 
rule that clarifies the scope of the Clean Water Act. The definition 
will apply to all provisions of the Act, and this regulation 
specifically amends EPA regulations implementing sections 301, 304, 
306, 311, 402 and 404, while the Army is making substantively identical 
revisions to its regulations under section 404 of the CWA. Section 
511(c) of the Clean Water Act provides that, except for certain actions 
not relevant here, no action by EPA constitutes `a major federal action 
significantly affecting the quality of the human environment within the 
meaning of [NEPA]''.
    The Army has prepared a final environmental assessment and Findings 
of No Significant Impact consistent with the National Environmental 
Policy Act (NEPA). The Army has determined that the rule is not a major 
federal action significantly affecting the quality of the human 
environment that would require the preparation of an environmental 
impact statement. The assessment is contained in the record for this 
rulemaking. Furthermore, appropriate environmental documentation, 
including an EIS when required, is prepared by the Corps for general 
permits and specifically for each and every standard individual permit 
application before making final permit decisions.

M. Judicial Review

    Section 509(b)(1) of the CWA provides for judicial review in the 
courts of appeals of specifically enumerated actions of the 
Administrator. The Supreme Court and lower courts have reached 
different conclusions on the types of actions that fall within section 
509. Compare, E.I. du Pont de Nemours and Co. v. Train, 430 U.S. 112 
(1977); NRDC v. EPA, 673 F.2d 400 (D.C. Cir. 1982); National Cotton 
Council of Amer. v. EPA, 553 F.3d 927(6th Cir. 2009) cert denied 559 
U.S. 936 (2010) with, Northwest Environmental Advocates v. EPA, 537 
F.3d 1006 (9th Cir. 2008); Friends of the Everglades v. EPA, 699 F.3d 
1280 (11th Cir. 2012) cert denied 559 U.S. 936 (2010).
    See DATES section for information regarding the timing for seeking 
judicial review of this rule.

List of Subjects

33 CFR Part 328

    Environmental protection, Administrative practice and procedure, 
Intergovernmental relations, Navigation, Water pollution control, 
Waterways.

40 CFR Parts 110, 112, 116, 117, 122, 230, 232, 300, 301, and 401

    Environmental protection, Water pollution control.

    Dated: May 27, 2015.
Gina McCarthy,
Administrator, Environmental Protection Agency.
    Dated: May 27, 2015.
Jo-Ellen Darcy,
Assistant Secretary of the Army, (Civil Works), Department of the Army.

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 amended as follows:

PART 328--DEFINITION OF WATERS OF THE UNITED STATES

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

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

0
2. Section 328.3 is amended by revising paragraphs (a) through (c), 
removing paragraphs (d) and (e), and redesignating paragraph (f) as 
paragraph (d) to read as follows:

Sec.  328.3  Definitions.

* * * * *
    (a) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(b) of this section, the term ``waters of the United States'' means:
    (1) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (2) All interstate waters, including interstate wetlands;
    (3) The territorial seas;
    (4) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (5) All tributaries, as defined in paragraph (c)(3) of this 
section, of waters identified in paragraphs (a)(1) through (3) of this 
section;
    (6) All waters adjacent to a water identified in paragraphs (a)(1) 
through (5) of this section, including wetlands, ponds, lakes, oxbows, 
impoundments, and similar waters;
    (7) All waters in paragraphs (a)(7)(i) through (v) of this section 
where they are determined, on a case-specific basis, to have a 
significant nexus to a water identified in paragraphs (a)(1) through 
(3) of this section. The waters identified in each of paragraphs 
(a)(7)(i) through (v) of this section are similarly situated and shall 
be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(a)(1)

[[Page 37105]]

through (3) of this section. Waters identified in this paragraph shall 
not be combined with waters identified in paragraph (a)(6) of this 
section when performing a significant nexus analysis. If waters 
identified in this paragraph are also an adjacent water under paragraph 
(a)(6), they are an adjacent water and no case-specific significant 
nexus analysis is required.
    (i) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (ii) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (iii) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (iv) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (v) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (8) All waters located within the 100-year floodplain of a water 
identified in paragraphs (a)(1) through (3) of this section and all 
waters located within 4,000 feet of the high tide line or ordinary high 
water mark of a water identified in paragraphs (a)(1) through (5) of 
this section where they are determined on a case-specific basis to have 
a significant nexus to a water identified in paragraphs (a)(1) through 
(3) of this section. For waters determined to have a significant nexus, 
the entire water is a water of the United States if a portion is 
located within the 100-year floodplain of a water identified in 
paragraphs (a)(1) through (3) of this section or within 4,000 feet of 
the high tide line or ordinary high water mark. Waters identified in 
this paragraph shall not be combined with waters identified in 
paragraph (a)(6) of this section when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (a)(6), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (b) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (a)(4) through (8) of 
this section.
    (1) Waste treatment systems, including treatment ponds or lagoons 
designed to meet the requirements of the Clean Water Act.
    (2) Prior converted cropland. Notwithstanding the determination of 
an area's status as prior converted cropland by any other Federal 
agency, for the purposes of the Clean Water Act, the final authority 
regarding Clean Water Act jurisdiction remains with EPA.
    (3) The following ditches:
    (i) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (ii) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (iii) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (a)(1) through (3) of this 
section.
    (4) The following features:
    (i) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (ii) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (iii) Artificial reflecting pools or swimming pools created in dry 
land;
    (iv) Small ornamental waters created in dry land;
    (v) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (vi) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (vii) Puddles.
    (5) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (6) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (7) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (c) Definitions. In this section, the following definitions apply:
    (1) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (a)(1) through (5) of this 
section, including waters separated by constructed dikes or barriers, 
natural river berms, beach dunes, and the like. For purposes of 
adjacency, an open water such as a pond or lake includes any wetlands 
within or abutting its ordinary high water mark. Adjacency is not 
limited to waters located laterally to a water identified in paragraphs 
(a)(1) through (5) of this section. Adjacent waters also include all 
waters that connect segments of a water identified in paragraphs (a)(1) 
through (5) or are located at the head of a water identified in 
paragraphs (a)(1) through (5) of this section and are bordering, 
contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (2) Neighboring. The term neighboring means:
    (i) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (a)(1) through (5) of this 
section. The entire water is neighboring if a portion is located within 
100 feet of the ordinary high water mark;
    (ii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (a)(1) through (5) of this section and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (iii) All waters located within 1,500 feet of the high tide line of 
a water identified in paragraphs (a)(1) or (a)(3) of this section, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (3) Tributary and tributaries. The terms tributary and tributaries 
each mean a water that contributes flow, either directly or through 
another water (including an impoundment identified in paragraph (a)(4) 
of this section), to a water identified in paragraphs (a)(1) through 
(3) of this section that is characterized by the presence of the 
physical indicators of a bed and banks and an ordinary high water mark. 
These physical indicators demonstrate there is volume, frequency, and 
duration of flow sufficient to create a bed and banks and an ordinary 
high water mark, and thus to qualify as a tributary. A tributary can be 
a natural, man-altered, or man-made water and includes waters such as 
rivers, streams, canals, and ditches not excluded under paragraph (b) 
of this

[[Page 37106]]

section. A water that otherwise qualifies as a tributary under this 
definition does not lose its status as a tributary if, for any length, 
there are one or more constructed breaks (such as bridges, culverts, 
pipes, or dams), or one or more natural breaks (such as wetlands along 
the run of a stream, debris piles, boulder fields, or a stream that 
flows underground) so long as a bed and banks and an ordinary high 
water mark can be identified upstream of the break. A water that 
otherwise qualifies as a tributary under this definition does not lose 
its status as a tributary if it contributes flow through a water of the 
United States that does not meet the definition of tributary or through 
a non-jurisdictional water to a water identified in paragraphs (a)(1) 
through (3) of this section.
    (4) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (5) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (a)(1) through (3) of this section. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (a)(1) through (3) of this section. For an 
effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream paragraph (a)(1) 
through (3) waters shall be assessed by evaluating the aquatic 
functions identified in paragraphs (c)(5)(i) through (ix) of this 
section. A water has a significant nexus when any single function or 
combination of functions performed by the water, alone or together with 
similarly situated waters in the region, contributes significantly to 
the chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (a)(1) through (3) of this section. Functions 
relevant to the significant nexus evaluation are the following:
    (i) Sediment trapping,
    (ii) Nutrient recycling,
    (iii) Pollutant trapping, transformation, filtering, and transport,
    (iv) Retention and attenuation of flood waters,
    (v) Runoff storage,
    (vi) Contribution of flow,
    (vii) Export of organic matter,
    (viii) Export of food resources, and
    (ix) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (a)(1) 
through (3) of this section.
    (6) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (7) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

Title 40--Protection of Environment

    For reasons set out in the preamble, title 40, chapter I of the 
Code of Federal Regulations is amended as follows:

PART 110--DISCHARGE OF OIL

0
3. The authority citation for part 110 is revised to read as follows:

    Authority: 33 U.S.C. 1251 et seq., 33 U.S.C. 1321(b)(3) and 
(b)(4) and 1361(a); E.O. 11735, 38 FR 21243, 3 CFR parts 1971-1975 
Comp., p. 793.

0
4. Section 110.1 is amended by removing the definition of ``wetlands'' 
and revising the definition of ``navigable waters'' to read as follows:

Sec.  110.1  Definitions.

* * * * *
    Navigable waters means waters of the United States, including the 
territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this section, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.

[[Page 37107]]

    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this section.
    (i) Waste treatment systems (other than cooling ponds meeting the 
criteria of this paragraph) are not waters of the United States.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(1) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (iii) of this definition, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this section), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.

[[Page 37108]]

    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this definition.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 112--OIL POLLUTION PREVENTION

0
5. The authority citation for part 112 is revised to read as follows:

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

0
6. Section 112.2 is amended by removing the definition of ``wetlands'' 
and revising the definition of ``Navigable waters'' to read as follows:

Sec.  112.2  Definitions.

* * * * *
    Navigable waters means waters of the United States, including the 
territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this section when performing a significant nexus analysis. 
If waters identified in this paragraph are also an adjacent water under 
paragraph (1)(vi), they are an adjacent water and no case-specific 
significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the

[[Page 37109]]

100-year floodplain of a water identified in paragraphs (1)(i) through 
(iii) of this definition or within 4,000 feet of the high tide line or 
ordinary high water mark. Waters identified in this paragraph shall not 
be combined with waters identified in paragraph (1)(vi) of this 
definition when performing a significant nexus analysis. If waters 
identified in this paragraph are also an adjacent water under paragraph 
(1)(vi), they are an adjacent water and no case-specific significant 
nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (ii) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (iii) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (iv) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (v) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (1)(iii) of this definition, 
and all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the

[[Page 37110]]

chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this section. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this definition.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 116--DESIGNATION OF HAZARDOUS SUBSTANCE

0
7. The authority citation for part 116 is revised to read as follows:

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

0
8. Section 116.3 is amended by revising the definition of ``Navigable 
waters'' to read as follows:

Sec.  116.3  Definitions.

* * * * *
    Navigable waters is defined in section 502(7) of the Act to mean 
``waters of the United States, including the territorial seas.''
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) 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.
    (ii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iii) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;

[[Page 37111]]

    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (iv) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (v) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vi) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (1)(iii) of this definition, 
and all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider

[[Page 37112]]

the characteristics of the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 117--DETERMINATION OF REPORTABLE QUANTITIES FOR HAZARDOUS 
SUBSTANCES

0
9. The authority citation for part 117 is revised to read as follows:

    Authority: 33 U.S.C. 1251 et seq. and Executive Order 11735, 
superseded by Executive Order 12777, 56 FR 54757.

0
10. Section 117.1 is amended by revising paragraph (i) to read as 
follows:

Sec.  117.1  Definitions.

* * * * *
    (i) Navigable waters is defined in section 502(7) of the Act to 
mean ``waters of the United States, including the territorial seas.''
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(i)(2) of this section, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (i)(3)(iii) of this 
section, of waters identified in paragraphs (i)(1)(i) through (iii) of 
this section;
    (vi) All waters adjacent to a water identified in paragraphs 
(i)(1)(i) through (v) of this section, including wetlands, ponds, 
lakes, oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (i)(1)(vii)(A) through (E) of this 
section where they are determined, on a case-specific basis, to have a 
significant nexus to a water identified in paragraphs (i)(1)(i) through 
(iii) of this section. The waters identified in each of paragraphs 
(i)(1)(vii)(A) through (E) of this section are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(i)(1)(i) through (iii) of this section. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(i)(1)(vi) of this section when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (i)(1)(vi), they are an adjacent water and no 
case-specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in (i)(1)(i) through (iii) of this section and all waters 
located within 4,000 feet of the high tide line or ordinary high water 
mark of a water identified in paragraphs (i)(1)(i) through (v) of this 
section where they are determined on a case-specific basis to have a 
significant nexus to a water identified in paragraphs (i)(1)(i) through 
(iii) of this section. For waters determined to have a significant 
nexus, the entire water is a water of the United States if a portion is 
located within the 100-year floodplain of a water identified in 
paragraphs (i)(1)(i) through (iii) of this section or within 4,000 feet 
of the high tide line or ordinary high water mark. Waters identified in 
this paragraph shall not be combined with waters identified in 
paragraph (i)(1)(vi) of this section when performing a significant 
nexus analysis. If waters identified in this paragraph are also an 
adjacent water under paragraph (i)(1)(vi), they are an adjacent water 
and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (i)(1)(iv) through 
(viii) of this section.
    (i) Waste treatment systems, (other than cooling ponds meeting the 
criteria of this paragraph) are not waters of the United States.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (i)(1)(i) through (iii) of 
this section.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.

[[Page 37113]]

    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this paragraph, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (i)(1)(i) through (v) of 
this section, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (i)(1)(i) through (v) of this section. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (i)(1)(i) through (v) or are located at the head of a water 
identified in paragraphs (i)(1)(i) through (v) of this section and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (i)(1)(i) through (v) of this 
section. The entire water is neighboring if a portion is located within 
100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (i)(1)(i) through (v) of this section and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (i)(1)(i) or (iii) of this section, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(i)(1)(iv) of this section), to a water identified in paragraphs 
(i)(1)(i) through (iii) of this section that is characterized by the 
presence of the physical indicators of a bed and banks and an ordinary 
high water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (i)(2) of this section. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (i)(1)(i) through (iii) of this section.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (i)(1)(i) through (iii) of this section. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (i)(1)(i) through (iii) of this section. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (i)(1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (i)(3)(v)(A) through (I) of this section. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (i)(1)(i) through (iii) of this section. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (i)(1)(i) 
through (iii) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

[[Page 37114]]

PART 122--EPA ADMINISTERED PERMIT PROGRAMS: THE NATIONAL POLLUTANT 
DISCHARGE ELIMINATION SYSTEM

0
11. The authority citation for part 122 continues to read as follows:

    Authority:  The Clean Water Act, 33 U.S.C. 1251 et seq.

0
12. Section 122.2 is amended by:
0
a. Lifting the suspension of the last sentence of the definition of 
``Waters of the United States'' published July 21, 1980 (45 FR 48620);
0
b. Removing the definition of ``wetlands'' and revising the definition 
of ``Waters of the United States'' and
0
c. Suspending the last sentence of the definition of ``Waters of the 
United States'' published July 21, 1980 (45 FR 48620).
    The revision reads as follows:

Sec.  122.2  Definitions.

* * * * *
    Waters of the United States or waters of the U.S. means:
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
section, of waters identified in paragraphs (1)(i) through (iii) of 
this section;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (v) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in (1)(i) through (iii) of this definition or within 4,000 
feet of the high tide line or ordinary high water mark. Waters 
identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) Waste treatment systems, including treatment ponds or lagoons 
designed to meet the requirements of the Clean Water Act. 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. [See Note 1 of this section.]
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:

[[Page 37115]]

    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (iii) of this definition, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this definition.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 230--SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF 
DISPOSAL SITES FOR DREDGED OR FILL MATERIAL

0
13. The authority citation for part 230 is revised to read as follows:

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

0
14. Section 230.3 is amended by:
0
a. Removing paragraph (b) and reserved paragraphs (f), (g), (j) and 
(l).

[[Page 37116]]

0
b. Redesignating paragraphs (c) through (e) as paragraphs (b) through 
(d).
0
c. Redesignating paragraphs (h) and (i) as paragraphs (e) and (f).
0
d. Redesignating paragraph (k) as paragraph (g).
0
e. Redesignating paragraphs (m) through (q) as paragraphs (h) through 
(l).
0
f. Redesignating paragraph (q-1) as paragraph (m).
0
g. Redesignating paragraph (r) as paragraph (n).
0
h. Redesignating paragraph (s) as paragraph (o).
0
i. Revising newly redesignated paragraph (o).
0
j. Removing paragraph (t).
    The revision reads as follows:

Sec.  230.3  Definitions.

* * * * *
    (o) The term waters of the United States means:
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(o)(2) of this section, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (o)(3)(iii) of this 
section, of waters identified in paragraphs (o)(1)(i) through (iii) of 
this section;
    (vi) All waters adjacent to a water identified in paragraphs 
(o)(1)(i) through (v) of this section, including wetlands, ponds, 
lakes, oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (o)(1)(vii)(A) through (E) of this 
section where they are determined, on a case-specific basis, to have a 
significant nexus to a water identified in paragraphs (o)(1)(i) through 
(iii) of this section. The waters identified in each of paragraphs 
(o)(1)(vii)(A) through (E) of this section are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(o)(1)(i) through (iii) of this section. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(o)(1)(vi) of this section when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (o)(1)(vi), they are an adjacent water and no 
case-specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (o)(1)(i) through (iii) of this section and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (o)(1)(i) through 
(v) of this section where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs 
(o)(1)(i) through (iii) of this section. For waters determined to have 
a significant nexus, the entire water is a water of the United States 
if a portion is located within the 100-year floodplain of a water 
identified in paragraphs (o)(1)(i) through (iii) of this section or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (o)(1)(vi) of this section when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (o)(1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (o)(1)(iv) through 
(viii) of this section.
    (i) 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.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (o)(1)(i) through (iii) of 
this section.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this paragraph (o), the following definitions apply:

    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (o)(1)(i) through (v) of 
this section, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of

[[Page 37117]]

adjacency, an open water such as a pond or lake includes any wetlands 
within or abutting its ordinary high water mark. Adjacency is not 
limited to waters located laterally to a water identified in paragraphs 
(o)(1)(i) through (v) of this section. Adjacent waters also include all 
waters that connect segments of a water identified in paragraphs 
(o)(1)(i) through (v) or are located at the head of a water identified 
in paragraphs (o)(1)(i) through (v) of this section and are bordering, 
contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (o)(1)(i) through (v) of this 
section. The entire water is neighboring if a portion is located within 
100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (o)(1)(i) through (v) of this section and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (o)(1)(i) or (iii) of this section, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(o)(1)(iv) of this section), to a water identified in paragraphs 
(o)(1)(i) through (iii) of this section that is characterized by the 
presence of the physical indicators of a bed and banks and an ordinary 
high water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (o)(2) of this section. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (o)(1)(i) through (iii) of this section.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (o)(1)(i) through (iii) of this section. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (o)(1)(i) through (iii) of this section. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (o)(1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (o)(3)(v)(A) through (I) of this section. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (o)(1)(i) through (iii) of this section. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (o)(1) 
through (3) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 232--404 PROGRAMS DEFINITIONS; EXEMPT ACTIVITIES NOT REQUIRING 
404 PERMITS

0
15. The authority citation for part 230 is revised to read as follows:

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

0
16. Section 232.2 is amended by removing the definition of ``wetlands'' 
and revising the definition of ``Waters of the United States'' to read 
as follows:

Sec.  232.2  Definitions.

* * * * *
    Waters of the United States means:
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this

[[Page 37118]]

definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi) of this definition, they 
are an adjacent water and no case-specific significant nexus analysis 
is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) 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.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;

[[Page 37119]]

    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (1)(iii) of this definition, 
and all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this definition.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 300--NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION 
CONTINTENCY PLAN

0
17. The authority citation for part 300 is revised to read as follows:

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

0
18. Section 300.5 is amended by revising the definition of ``navigable 
waters'' to read as follows:

Sec.  300.5  Definitions.

* * * * *
    Navigable waters means the waters of the United States, including 
the territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition

[[Page 37120]]

where they are determined, on a case-specific basis, to have a 
significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) Waste treatment systems (other than cooling ponds meeting the 
criteria of this paragraph) are not waters of the United States.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (1)(iii) of this definition, 
and all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is

[[Page 37121]]

characterized by the presence of the physical indicators of a bed and 
banks and an ordinary high water mark. These physical indicators 
demonstrate there is volume, frequency, and duration of flow sufficient 
to create a bed and banks and an ordinary high water mark, and thus to 
qualify as a tributary. A tributary can be a natural, man-altered, or 
man-made water and includes waters such as rivers, streams, canals, and 
ditches not excluded under paragraph (2) of this definition. A water 
that otherwise qualifies as a tributary under this definition does not 
lose its status as a tributary if, for any length, there are one or 
more constructed breaks (such as bridges, culverts, pipes, or dams), or 
one or more natural breaks (such as wetlands along the run of a stream, 
debris piles, boulder fields, or a stream that flows underground) so 
long as a bed and banks and an ordinary high water mark can be 
identified upstream of the break. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if it contributes flow through a water of the United States that does 
not meet the definition of tributary or through a non-jurisdictional 
water to a water identified in paragraphs (1)(i) through (iii) of this 
definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this definition.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

0
19. In appendix E to part 300, section 1.5 Definitions is amended by 
revising the definition of ``navigable waters'' to read as follows:

Appendix E to Part 300--Oil Spill Response

* * * * *

1.5 Definitions. * * *

    Navigable waters means the waters of the United States, including 
the territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands

[[Page 37122]]

found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus, the entire water is a water of the United States if 
a portion is located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition or 
within 4,000 feet of the high tide line or ordinary high water mark. 
Waters identified in this paragraph shall not be combined with waters 
identified in paragraph (1)(vi) of this definition when performing a 
significant nexus analysis. If waters identified in this paragraph are 
also an adjacent water under paragraph (1)(vi), they are an adjacent 
water and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) Waste treatment systems (other than cooling ponds meeting the 
criteria of this paragraph) are not waters of the United States.
    (ii) 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.
    (iii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (iv) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (v) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (vi) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vii) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (1)(iii) of this definition, 
and all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified

[[Page 37123]]

in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 302--DESIGNATION, REPORTABLE QUANTITIES, AND NOTIFICATION

0
20. The authority citation for part 302 is revised to read as follows:

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

0
21. Section 302.3 is amended by revising the definition of ``Navigable 
waters'' to read as follows:

Sec.  302.3  Definitions.

* * * * *
    Navigable waters means the waters of the United States, including 
the territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(2) of this definition, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (3)(iii) of this 
definition, of waters identified in paragraphs (1)(i) through (iii) of 
this definition;
    (vi) All waters adjacent to a water identified in paragraphs (1)(i) 
through (v) of this definition, including wetlands, ponds, lakes, 
oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (1)(vii)(A) through (E) of this 
definition where they are determined, on a case-specific basis, to have 
a significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this definition. The waters identified in each of paragraphs 
(1)(vii)(A) through (E) of this definition are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(1)(i) through (iii) of this definition. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(1)(vi) of this definition when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (1)(vi), they are an adjacent water and no case-
specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (iii) of this definition and 
all waters located within 4,000 feet of the high tide line or ordinary 
high water mark of a water identified in paragraphs (1)(i) through (v) 
of this definition where they are determined on a case-specific basis 
to have a significant nexus to a water identified in paragraphs (1)(i) 
through (iii) of this definition. For waters determined to have a 
significant nexus,

[[Page 37124]]

the entire water is a water of the United States if a portion is 
located within the 100-year floodplain of a water identified in 
paragraphs (1)(i) through (iii) of this definition or within 4,000 feet 
of the high tide line or ordinary high water mark. Waters identified in 
this paragraph shall not be combined with waters identified in 
paragraph (1)(vi) of this definition when performing a significant 
nexus analysis. If waters identified in this paragraph are also an 
adjacent water under paragraph (1)(vi), they are an adjacent water and 
no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (1)(iv) through 
(viii) of this definition.
    (i) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (1)(i) through (iii) of 
this definition.
    (ii) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;
    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (iii) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (iv) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (v) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this definition, the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (1)(i) through (v) of this 
definition, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (1)(i) through (v) of this definition. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (1)(i) through (v) or are located at the head of a water 
identified in paragraphs (1)(i) through (v) of this definition and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (1)(i) through (v) of this 
definition. The entire water is neighboring if a portion is located 
within 100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (1)(i) through (v) of this definition and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (1)(i) or (iii) of this definition, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(1)(iv) of this definition), to a water identified in paragraphs (1)(i) 
through (iii) of this definition that is characterized by the presence 
of the physical indicators of a bed and banks and an ordinary high 
water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (2) of this definition. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (1)(i) through (iii) of this definition.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (1)(i) through (iii) of this definition. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (3)(v)(A) through (I) of this definition. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with

[[Page 37125]]

similarly situated waters in the region, contributes significantly to 
the chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (1)(i) through (iii) of this definition. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (1)(i) 
through (iii) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.
    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *

PART 401--GENERAL PROVISIONS

0
22. The authority citation for part 401 is revised to read as follows:

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

0
23. Section 401.11 is amended by revising paragraph (l) to read as 
follows:

Sec.  401.11  General definitions.

* * * * *
    (l) The term navigable waters means the waters of the United 
States, including the territorial seas.
    (1) For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and 
its implementing regulations, subject to the exclusions in paragraph 
(l)(2) of this section, the term ``waters of the United States'' means:
    (i) All waters which are currently used, were used in the past, or 
may be susceptible to use in interstate or foreign commerce, including 
all waters which are subject to the ebb and flow of the tide;
    (ii) All interstate waters, including interstate wetlands;
    (iii) The territorial seas;
    (iv) All impoundments of waters otherwise identified as waters of 
the United States under this section;
    (v) All tributaries, as defined in paragraph (l)(3)(iii) of this 
section, of waters identified in paragraphs (l)(1)(i) through (iii) of 
this section;
    (vi) All waters adjacent to a water identified in paragraphs 
(l)(1)(i) through (v) of this section, including wetlands, ponds, 
lakes, oxbows, impoundments, and similar waters;
    (vii) All waters in paragraphs (l)(1)(vii)(A) through (E) of this 
section where they are determined, on a case-specific basis, to have a 
significant nexus to a water identified in paragraphs (1)(i) through 
(iii) of this section. The waters identified in each of paragraphs 
(l)(1)(vii)(A) through (E) of this section are similarly situated and 
shall be combined, for purposes of a significant nexus analysis, in the 
watershed that drains to the nearest water identified in paragraphs 
(l)(1)(i) through (iii) of this section. Waters identified in this 
paragraph shall not be combined with waters identified in paragraph 
(l)(1)(vi) of this section when performing a significant nexus 
analysis. If waters identified in this paragraph are also an adjacent 
water under paragraph (l)(1)(vi), they are an adjacent water and no 
case-specific significant nexus analysis is required.
    (A) Prairie potholes. Prairie potholes are a complex of glacially 
formed wetlands, usually occurring in depressions that lack permanent 
natural outlets, located in the upper Midwest.
    (B) Carolina bays and Delmarva bays. Carolina bays and Delmarva 
bays are ponded, depressional wetlands that occur along the Atlantic 
coastal plain.
    (C) Pocosins. Pocosins are evergreen shrub and tree dominated 
wetlands found predominantly along the Central Atlantic coastal plain.
    (D) Western vernal pools. Western vernal pools are seasonal 
wetlands located in parts of California and associated with topographic 
depression, soils with poor drainage, mild, wet winters and hot, dry 
summers.
    (E) Texas coastal prairie wetlands. Texas coastal prairie wetlands 
are freshwater wetlands that occur as a mosaic of depressions, ridges, 
intermound flats, and mima mound wetlands located along the Texas Gulf 
Coast.
    (viii) All waters located within the 100-year floodplain of a water 
identified in (l)(1)(i) through (iii) of this section and all waters 
located within 4,000 feet of the high tide line or ordinary high water 
mark of a water identified in paragraphs (l)(1)(i) through (v) of this 
section where they are determined on a case-specific basis to have a 
significant nexus to a water identified in paragraphs (l)(1)(i) through 
(iii) of this section. For waters determined to have a significant 
nexus, the entire water is a water of the United States if a portion is 
located within the 100-year floodplain of a water identified in 
paragraphs (l)(1)(i) through (iii) of this section or within 4,000 feet 
of the high tide line or ordinary high water mark. Waters identified in 
this paragraph shall not be combined with waters identified in 
paragraph (l)(1)(vi) of this section when performing a significant 
nexus analysis. If waters identified in this paragraph are also an 
adjacent water under paragraph (l)(1)(vi), they are an adjacent water 
and no case-specific significant nexus analysis is required.
    (2) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (l)(1)(iv) through 
(viii) of this section.
    (i) 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.
    (ii) The following ditches:
    (A) Ditches with ephemeral flow that are not a relocated tributary 
or excavated in a tributary.
    (B) Ditches with intermittent flow that are not a relocated 
tributary, excavated in a tributary, or drain wetlands.
    (C) Ditches that do not flow, either directly or through another 
water, into a water identified in paragraphs (l)(1)(i) through (iii) of 
this section.
    (iii) The following features:
    (A) Artificially irrigated areas that would revert to dry land 
should application of water to that area cease;

[[Page 37126]]

    (B) Artificial, constructed lakes and ponds created in dry land 
such as farm and stock watering ponds, irrigation ponds, settling 
basins, fields flooded for rice growing, log cleaning ponds, or cooling 
ponds;
    (C) Artificial reflecting pools or swimming pools created in dry 
land;
    (D) Small ornamental waters created in dry land;
    (E) Water-filled depressions created in dry land incidental to 
mining or construction activity, including pits excavated for obtaining 
fill, sand, or gravel that fill with water;
    (F) Erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; and
    (G) Puddles.
    (iv) Groundwater, including groundwater drained through subsurface 
drainage systems.
    (v) Stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land.
    (vi) Wastewater recycling structures constructed in dry land; 
detention and retention basins built for wastewater recycling; 
groundwater recharge basins; percolation ponds built for wastewater 
recycling; and water distributary structures built for wastewater 
recycling.
    (3) In this paragraph (l), the following terms apply:
    (i) Adjacent. The term adjacent means bordering, contiguous, or 
neighboring a water identified in paragraphs (l)(1)(i) through (v) of 
this section, including waters separated by constructed dikes or 
barriers, natural river berms, beach dunes, and the like. For purposes 
of adjacency, an open water such as a pond or lake includes any 
wetlands within or abutting its ordinary high water mark. Adjacency is 
not limited to waters located laterally to a water identified in 
paragraphs (l)(1)(i) through (v) of this section. Adjacent waters also 
include all waters that connect segments of a water identified in 
paragraphs (l)(1)(i) through (v) or are located at the head of a water 
identified in paragraphs (l)(1)(i) through (v) of this section and are 
bordering, contiguous, or neighboring such water. Waters being used for 
established normal farming, ranching, and silviculture activities (33 
U.S.C. 1344(f)) are not adjacent.
    (ii) Neighboring. The term neighboring means:
    (A) All waters located within 100 feet of the ordinary high water 
mark of a water identified in paragraphs (l)(1)(i) through (v) of this 
section. The entire water is neighboring if a portion is located within 
100 feet of the ordinary high water mark;
    (B) All waters located within the 100-year floodplain of a water 
identified in paragraphs (l)(1)(i) through (v) of this section and not 
more than 1,500 feet from the ordinary high water mark of such water. 
The entire water is neighboring if a portion is located within 1,500 
feet of the ordinary high water mark and within the 100-year 
floodplain;
    (C) All waters located within 1,500 feet of the high tide line of a 
water identified in paragraphs (l)(1)(i) or (iii) of this section, and 
all waters within 1,500 feet of the ordinary high water mark of the 
Great Lakes. The entire water is neighboring if a portion is located 
within 1,500 feet of the high tide line or within 1,500 feet of the 
ordinary high water mark of the Great Lakes.
    (iii) Tributary and tributaries. The terms tributary and 
tributaries each mean a water that contributes flow, either directly or 
through another water (including an impoundment identified in paragraph 
(l)(1)(iv) of this section), to a water identified in paragraphs 
(l)(1)(i) through (iii) of this section that is characterized by the 
presence of the physical indicators of a bed and banks and an ordinary 
high water mark. These physical indicators demonstrate there is volume, 
frequency, and duration of flow sufficient to create a bed and banks 
and an ordinary high water mark, and thus to qualify as a tributary. A 
tributary can be a natural, man-altered, or man-made water and includes 
waters such as rivers, streams, canals, and ditches not excluded under 
paragraph (l)(2) of this section. A water that otherwise qualifies as a 
tributary under this definition does not lose its status as a tributary 
if, for any length, there are one or more constructed breaks (such as 
bridges, culverts, pipes, or dams), or one or more natural breaks (such 
as wetlands along the run of a stream, debris piles, boulder fields, or 
a stream that flows underground) so long as a bed and banks and an 
ordinary high water mark can be identified upstream of the break. A 
water that otherwise qualifies as a tributary under this definition 
does not lose its status as a tributary if it contributes flow through 
a water of the United States that does not meet the definition of 
tributary or through a non-jurisdictional water to a water identified 
in paragraphs (l)(1)(i) through (iii) of this section.
    (iv) Wetlands. The term wetlands means those areas that are 
inundated or saturated by surface or groundwater 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.
    (v) Significant nexus. The term significant nexus means that a 
water, including wetlands, either alone or in combination with other 
similarly situated waters in the region, significantly affects the 
chemical, physical, or biological integrity of a water identified in 
paragraphs (l)(1)(i) through (iii) of this section. The term ``in the 
region'' means the watershed that drains to the nearest water 
identified in paragraphs (l)(1)(i) through (iii) of this section. For 
an effect to be significant, it must be more than speculative or 
insubstantial. Waters are similarly situated when they function alike 
and are sufficiently close to function together in affecting downstream 
waters. For purposes of determining whether or not a water has a 
significant nexus, the water's effect on downstream (1)(i) through 
(iii) waters shall be assessed by evaluating the aquatic functions 
identified in paragraphs (l)(3)(v)(A) through (I) of this section. A 
water has a significant nexus when any single function or combination 
of functions performed by the water, alone or together with similarly 
situated waters in the region, contributes significantly to the 
chemical, physical, or biological integrity of the nearest water 
identified in paragraphs (l)(1)(i) through (iii) of this section. 
Functions relevant to the significant nexus evaluation are the 
following:
    (A) Sediment trapping,
    (B) Nutrient recycling,
    (C) Pollutant trapping, transformation, filtering, and transport,
    (D) Retention and attenuation of flood waters,
    (E) Runoff storage,
    (F) Contribution of flow,
    (G) Export of organic matter,
    (H) Export of food resources, and
    (I) Provision of life cycle dependent aquatic habitat (such as 
foraging, feeding, nesting, breeding, spawning, or use as a nursery 
area) for species located in a water identified in paragraphs (l)(1)(i) 
through (iii) of this section.
    (vi) Ordinary high water mark. The term ordinary high water mark 
means that line on the shore established by the fluctuations of water 
and indicated by physical characteristics such as a clear, natural line 
impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.

[[Page 37127]]

    (vii) High tide line. The term high tide line means the line of 
intersection of the land with the water's surface at the maximum height 
reached by a rising tide. The high tide line may be determined, in the 
absence of actual data, by a line of oil or scum along shore objects, a 
more or less continuous deposit of fine shell or debris on the 
foreshore or berm, other physical markings or characteristics, 
vegetation lines, tidal gages, or other suitable means that delineate 
the general height reached by a rising tide. The line encompasses 
spring high tides and other high tides that occur with periodic 
frequency but does not include storm surges in which there is a 
departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.
* * * * *
[FR Doc. 2015-13435 Filed 6-26-15; 8:45 am]
 BILLING CODE 6560-50-P
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