EPA and the Army Corps’ Proposed Rule to
Define “Waters of the United States”

Claudia Copeland
Specialist in Resources and Environmental Policy
November 21, 2014
Congressional Research Service
7-5700
www.crs.gov
R43455


EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Summary
On March 25, 2014, the Environmental Protection Agency (EPA) and the U.S. Army Corps of
Engineers (Corps) jointly proposed a rule defining the scope of waters protected under the Clean
Water Act (CWA). The proposal would revise regulations that have been in place for more than
25 years. Revisions are proposed in light of 2001 and 2006 Supreme Court rulings that interpreted
the regulatory scope of the CWA more narrowly than previously, but created uncertainty about the
precise effect of the Court’s decisions.
According to the agencies, the proposed rule would revise the existing administrative definition
of “waters of the United States” consistent with legal rulings and science concerning the
interconnectedness of tributaries, wetlands, and other waters and effects of these connections on
the chemical, physical, and biological integrity of downstream waters. Waters that are
“jurisdictional” are subject to the multiple regulatory requirements of the CWA. Non-
jurisdictional waters are not subject to those requirements.
This report describes the proposed rule and includes a table comparing the existing regulatory
language that defines “waters of the United States” with the proposed revisions. The proposal is
particularly focused on clarifying the regulatory status of waters located in isolated places in a
landscape. It does not modify some categories of waters that currently are jurisdictional by rule
(traditional navigable waters, interstate waters and wetlands, the territorial seas, and
impoundments). The proposed rule would replace EPA-Corps guidance that was issued in 2003
and 2008, which has guided agency interpretation of the Court’s rulings but also has caused
considerable confusion.
Beyond the categories of waters that would be categorically jurisdictional under the proposal are
“other waters.” The regulatory term “other waters” applies to wetlands and non-wetland waters
such as prairie potholes that are not considered traditionally navigable or meet other of the
proposed rule’s jurisdictional definitions. Much of the controversy since the Supreme Court
rulings has focused on the degree to which “other waters” are jurisdictional. According to the
agencies’ analyses, 17% of these “other waters” would be categorically jurisdictional under the
proposal, but “other waters” that are not categorically jurisdictional would continue to need case-
by-case evaluation. The rule also lists waters and features that would not be jurisdictional, such as
prior converted cropland and certain ditches. It makes no change to existing statutory exclusions,
such as CWA permit exemptions for normal farming and ranching activities.
Proposed changes would increase the asserted scope of CWA jurisdiction, in part as a result of
expressly declaring some types of waters categorically jurisdictional (such as all waters adjacent
to a jurisdictional water), and also by application of definitions, which would give larger
regulatory context than previously to some waters, such as tributaries. Nevertheless, the agencies
believe that the proposal does not exceed the CWA’s coverage or protect new types of waters that
have not been protected historically. While it would enlarge jurisdiction beyond that under the
existing EPA-Corps guidance, they believe that it would not enlarge jurisdiction beyond what is
consistent with the Supreme Court’s narrow reading of jurisdiction and would reduce jurisdiction
over some waters, as a result of exclusions and exemptions. Others may disagree. The agencies
estimate that the rule would assert CWA jurisdiction over approximately 3% more U.S. waters
(e.g., by including additional “other waters”), compared with current field practice, but 5% less
than prior to the Supreme Court rulings (by specifically excluding some waters). Estimated costs,
principally from additional permitting requirements, range from $162 million to $279 million
Congressional Research Service

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

annually. Benefits are estimated to range from $318 million to $514 million annually.
Congressional hearings have been held, and the House has passed H.R. 5078 to bar issuance of
the rule and a related interpretive rule on agriculture exemptions. Other bills with provisions
addressing the “waters” proposal or interpretive rule include S. 2496, H.R. 4923, H.R. 5071, and
H.R. 5171.
The public comment period for the proposed rule closed November 14. EPA projects that a final
rule will be promulgated in April 2015.

Congressional Research Service

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Contents
Introduction ...................................................................................................................................... 1
The CWA and the Proposed Rule .................................................................................................... 2
“Other Waters” .......................................................................................................................... 4
Exclusions and Definitions ........................................................................................................ 5
Impacts of the Proposed Rule .......................................................................................................... 6
Concerns of Agriculture and Local Governments ..................................................................... 8
Conclusion and Legislative Responses .......................................................................................... 10

Tables
Table 1. Comparison of “Definition of Waters of the United States” Regulatory Language ......... 12

Appendixes
Appendix. EPA’s Draft Connectivity Report and Review by the Science Advisory Board ........... 21

Contacts
Author Contact Information........................................................................................................... 24

Congressional Research Service

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Introduction
On March 25, 2014, the Environmental Protection Agency (EPA) and the U.S. Army Corps of
Engineers (Corps) jointly proposed a rule defining the scope of waters protected under the Clean
Water Act (CWA). The proposed rule would revise regulations that have been in place for more
than 25 years.1 Revisions are proposed in light of Supreme Court rulings in 2001 and 2006 that
interpreted the regulatory scope of the CWA more narrowly than previously, but created
uncertainty about the precise effect of the Court’s decisions.2
In April 2011, EPA and the Corps proposed guidance on policies for determining CWA
jurisdiction to replace guidance previously issued in 2003 and 2008; all were intended to lessen
confusion over the Court’s rulings for the regulated community, regulators, and the general
public. The guidance documents sought to identify, in light of the Court’s rulings, categories of
waters that remain jurisdictional, categories not jurisdictional, and categories that require a case-
specific analysis to determine if CWA jurisdiction applies. The 2011 proposed guidance identified
similar categories as in the 2003 and 2008 documents, but it would have narrowed categories that
require case-specific analysis in favor of asserting jurisdiction categorically for some types of
waters. The 2014 proposed rule would replace the existing 2003 and 2008 guidance, which
remains in effect because the 2011 proposed guidance was not finalized.3
The 2011 proposed guidance was extremely controversial, especially with groups representing
property owners, land developers, and the agriculture sector, who contended that it represented a
massive federal overreach beyond the agencies’ statutory authority. Most state and local officials
were supportive of clarifying the extent of CWA-regulated waters, but some were concerned that
expanding the CWA’s scope could impose costs on states and localities as their own actions (e.g.,
transportation projects) become subject to new requirements. Most environmental advocacy
groups welcomed the proposed guidance, which would more clearly define U.S. waters that are
subject to CWA protections, but some in these groups favored even a stronger document. Still,
both supporters and critics of the 2011 proposed guidance urged the agencies to replace guidance
with revised regulations that define “waters of the United States.” Three opinions in the 2006
Supreme Court Rapanos ruling similarly urged the agencies to initiate a rulemaking, as they now
have done.
In Congress, a number of legislative proposals were introduced to bar EPA and the Corps from
implementing the 2011 proposed guidance or developing regulations based on it; none of these
proposals was enacted. Similar criticism followed almost immediately after release of the
proposed rule on March 25, 2014, with some Members asserting that the proposed rule would
result in job losses and would damage economic growth. Supporters of the Administration, on the
other hand, defended the agencies’ efforts to protect U.S. waters and reduce frustration that has

1 Definition of “waters of the United States” is found at 33 C.F.R. §328.3 (Corps) and 40 C.F.R. §122.2 (EPA). The
term is similarly defined in other EPA regulations, as is the term “navigable waters.” See Table 1.
2 Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (SWANCC), 531 U.S. 159 (2001),
and Rapanos v. United States, 547 U.S. 715 (2006).
3 For background on the Supreme Court rulings, subsequent guidance, and other developments, see CRS Report
RL33263, The Wetlands Coverage of the Clean Water Act (CWA): Rapanos and Beyond, by Robert Meltz and Claudia
Copeland.
Congressional Research Service
1

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

resulted from the unclear jurisdiction of the act.4 Support was expressed by environmental and
conservation organizations, among others.5
The CWA and the Proposed Rule
The proposed rule was published in the Federal Register on April 21, 2014. The public comment
period closed on November 14, 2014.6 Table 1 on page 11 in this report provides a comparison of
the current regulatory language that defines “waters of the United States” with language in the
proposed rule.
The CWA protects “navigable waters,” a term defined in the act to mean “the waters of the United
States, including the territorial seas.”7 Waters need not be truly navigable to be subject to CWA
jurisdiction. Both the legislative history and the case law surrounding the CWA confirm that
jurisdiction is not limited to traditional navigable waters, that is, waters that are, were, or could be
used in interstate or foreign commerce.8 Waters that are jurisdictional are subject to the multiple
regulatory requirements of the CWA: standards, discharge limitations, permits, and enforcement.
Non-jurisdictional waters, in contrast, do not have the federal legal protection of those
requirements. The act’s single definition of “navigable waters” applies to the entire law. In
particular, it applies to federal prohibition on discharges of pollutants except in compliance with
the act’s requirements (§301), requirements for point sources to obtain a permit prior to discharge
(§§402 and 404), water quality standards and measures to attain them (§303), oil spill liability
and oil spill prevention and control measures (§311), certification that federally permitted
activities comply with state water quality standards (§401), and enforcement (§309). It impacts
the Oil Pollution Act and other environmental laws, as well.9 The CWA leaves it to the agencies to
define the term “waters of the United States” in regulations, which EPA and the Corps have done
several times, most recently in 1986.
According to the agencies, the proposed rule would revise the existing administrative definition
of “waters of the United States” in regulations consistent with legal rulings—especially the recent
Supreme Court cases—and science concerning the interconnectedness of tributaries, wetlands,
and other waters to downstream waters and effects of these connections on the chemical,
physical, and biological integrity of downstream waters. It is particularly focused on clarifying
the regulatory status of waters located in isolated places in a landscape, the types of waters with
ambiguous jurisdictional status following the Supreme Court’s 2001 ruling in SWANCC, and
small streams, rivers that flow for part of the year, and nearby wetlands, the types of waters

4 Anthony Adragna and Amena Saiyid, “Republicans Contend EPA Overreached on Clean Water Act Jurisdiction
Proposal,” Daily Environment Report, vol. 58 (March 26, 2014), p. A-7.
5 U.S. Environmental Protection Agency, “Here’s What They're Saying About the Clean Water Act Proposed Rule,”
press release, March 26, 2014, http://yosemite.epa.gov/opa/admpress.nsf/3881d73f4d4aaa0b85257359003f5348/
3f954c179cf0720985257ca7004920fa.
6 Department of Defense, Department of the Army, Corps of Engineers, and Environmental Protection Agency,
“Definition of ‘Waters of the United States’ Under the Clean Water Act, Proposed Rule,” 79 Federal Register 22188-
22274, April 21, 2014. The agencies extended the original 90-day comment period twice.
7 CWA §502(7); 33 U.S.C. §1362(7).
8 United States v. Riverside Bayview Homes, Inc., 474 U.S. §121, 133 (1985).
9 For example, the reach of the Endangered Species Act (ESA) is affected, because that act’s requirement for
consultation by federal agencies over impacts on threatened or endangered species is triggered through the issuance of
federal permits.
Congressional Research Service
2

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

affected by the Court’s 2006 ruling in Rapanos. In developing the proposed rule, EPA and the
Corps relied on a draft synthesis of more than 1,000 published and peer-reviewed scientific
reports; the synthesis discusses the current scientific understanding of the connections or isolation
of streams and wetlands relative to large water bodies such as rivers, lakes, estuaries, and oceans.
The purpose of the scientific synthesis report is to summarize current understanding of these
connections, the factors that influence them, and the mechanisms by which connected waters
affect the function or condition of downstream waters.10 The document was reviewed by EPA’s
Science Advisory Board (SAB), which provides independent engineering and scientific advice to
the agency and which completed its review in October. Based on the SAB review, EPA will issue
a final scientific assessment report, likely early in 2015. A number of EPA’s critics suggested that
the agencies should have deferred developing or proposing a rule until a final scientific review
document is complete. In the preamble to the proposal, the agencies state that the rule will not be
finalized until the final report, reflecting the SAB review, is complete. However, some have
expressed concern that the final report will not be available during the public comment period on
the rule, which has now closed. (See the Appendix for discussion of the draft connectivity report
and review by the SAB.)
Under the first section of the proposed rule, the following waters would be jurisdictional by rule,
or, categorically jurisdictional:
• Waters susceptible to interstate commerce, known as traditional navigable waters
(no change from current rules);
• All interstate waters, including interstate wetlands (no change from current
rules);
• The territorial seas (no change from current rules);
• Impoundments of the above waters or a tributary, as defined in the rule (no
change from current rules);
• Tributaries of the above waters (these waters are jurisdictional under current
rules, but the term “tributary” is newly and broadly defined in the proposal); and
• All waters, including wetlands, that are adjacent to a water identified in the above
categories (by including all adjacent waters—not simply adjacent wetlands, as is
the case under current rules—the proposal is more inclusive than current rules in
finding these waters categorically jurisdictional; they are considered
jurisdictional under the proposed rule because the agencies conclude that they
have a significant nexus to a traditional navigable water, interstate water, or the
territorial seas).
The concept of significant nexus is critical because courts have ruled that, to establish CWA
jurisdiction of waters, there needs to be “some measure of the significance of the connection for
downstream water quality,” as Justice Kennedy stated in the 2006 Rapanos case. He said, “Mere
hydrologic connection should not suffice in all cases; the connection may be too insubstantial for
the hydrologic linkage to establish the required nexus with navigable waters as traditionally

10 U.S. Environmental Protection Agency, Office of Research and Development, Connectivity of Streams and Wetlands
to Downstream Waters: A Review and Synthesis of the Scientific Evidence, External Review Draft, EPA/600/R-11-
098B, September 2013, http://yosemite.epa.gov/sab/sabproduct.nsf/0/7724357376745F48852579E60043E88C/$File/
WOUS_ERD2_Sep2013.pdf.
Congressional Research Service
3

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

understood.”11 However, as EPA and the Corps observe in the proposed rule, significant nexus is
not itself a scientific term, but rather a determination of the agencies in light of the law and
science. Functions that might demonstrate significant nexus include sediment trapping and
retention of flood waters. In the proposed rule, the agencies note that a hydrologic connection is
not necessary to demonstrate significant nexus, because the function may be demonstrated even
in the absence of a connection (e.g., pollutant trapping is another such function).
“Other Waters”
Beyond the categories of waters that would be categorically jurisdictional under the proposed rule
is a category sometimes referred to as “other waters.” The regulatory term “other waters” applies
to wetlands and non-wetland waters that do not fall into the category of waters susceptible to
interstate commerce (traditional navigable waters), interstate waters, the territorial seas,
tributaries, or waters adjacent to waters in one of these four categories. Current regulations
contain a non-exclusive list of “other waters,” such as intrastate lakes, mudflats, prairie potholes,
and playa lakes (see Table 1). Headwaters, which constitute most “other waters,” supply most of
the water to downstream traditional navigable waters, interstate waters, and the territorial seas.
EPA and the Corps recognize that the Supreme Court decisions in SWANCC and Rapanos put
limitations on the scope of “other waters” that may be determined to be jurisdictional under the
CWA. Much of the controversy since the Court’s rulings has focused on uncertainty as to what
degree “other waters” are jurisdictional, either by definition/rule, or as determined on a case-by-
case basis to evaluate significant nexus to a jurisdictional water. Under the 2003 and 2008
guidance, which remain in effect today, all “other waters” require a case-by-case evaluation to
determine if a significant nexus exists, thus providing a finding of CWA jurisdiction. There
likewise has been uncertainty as to what degree “other waters” that are similarly situated may be
aggregated or combined for a significant nexus determination.12 Since issuing these guidance
documents, the agencies have not found jurisdiction over any “other water” based solely on
significant nexus.13 In the proposed rule, “other waters,” including wetlands, that are adjacent to a
jurisdictional water are categorically jurisdictional. Non-adjacent “other waters” and wetlands
will continue to require a case-by-case determination of significant nexus. Also, the proposed rule
allows broader aggregation of “other waters” that are similarly situated than under the existing
guidance,14 which could result in more “other waters” being found to be jurisdictional following a
significant nexus evaluation.
Some in the regulated community have urged EPA and the Corps to provide metrics, such as
quantifiable flow rates or minimum number of functions for “other waters,” to establish a
significant nexus to jurisdictional waters. The agencies declined to do so in the proposed rule,

11 547 U.S. at 784-785.
12 In the Rapanos ruling, Justice Kennedy stated 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.
13 The agencies have found some “other waters” jurisdictional because they meet another provision of the existing
definition of “waters of the United States,” such as a determination that the water is a traditional navigable water.
Personal communication, EPA Office of Water, May 23, 2014.
14 Under the proposed rule, “other waters” may be aggregated for a significant nexus determination if they perform
similar functions and are located sufficiently close together to be evaluated as a single landscape unit in the same
watershed with regard to their effect on a jurisdictional downstream water.
Congressional Research Service
4

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

saying that absolute standards would not allow sufficient flexibility to account for variability of
conditions and the varied functions that different waters provide.
The agencies acknowledge that there may be more than one way to determine which “other
waters” are jurisdictional, and they are requesting comment on alternate approaches, combination
of approaches, scientific and technical data, case law, and other information that would clarify
which “other waters” should be considered categorically jurisdictional or following a case-
specific significant nexus determination.
In addition, EPA and the Corps are asking for public comment on whether to conclude by rule
that certain types of “other waters”—prairie potholes, western vernal pools, Carolina and
Delmarva bays, pocosins, Texas coastal prairie wetlands, and perhaps other categories of
waters—have a significant nexus and are per se jurisdictional. These waters would not require a
case-by-case analysis. At the same time, the agencies are asking for comment on whether to
determine by rule that playa lakes and perhaps other categories of waters do not have a significant
nexus and are not jurisdictional. If so determined, these waters would not be subject to a case-by-
case analysis of significant nexus.
Exclusions and Definitions
The second section of the proposed rule excludes specified waters from the definition of “waters
of the United States.” The listed waters and features would not be jurisdictional even if they
would otherwise be included within categories that are jurisdictional. The exclusions are:
• Waste treatment systems, including treatment ponds or lagoons, that are designed
to meet CWA requirements (no change from current rules);
• Prior converted cropland (no change from current rules);
• A list of features that have been excluded by long-standing practice and guidance
and would now be excluded by rule, such as artificially irrigated areas that would
revert to upland should application of irrigation water to the area cease (see
Table 1 for the full list); and
• Two types of ditches: ditches that are excavated wholly in uplands, drain only
uplands or non-jurisdictional waters, and have less than perennial (i.e.,
permanent) flow; and ditches that do not contribute flow, either directly or
through another water, to a traditional navigable water, interstate water,
impoundment, or the territorial seas (even if the ditch has a perennial flow).
Other ditches, if they meet the rule’s definition of “tributary,” would continue to
be “waters of the United States”—a point of much controversy with some
stakeholders.
The proposed rule makes no change to and does not affect existing statutory and regulatory
exclusions: exemptions for normal farming, ranching, and silviculture activities such as plowing,
seeding, and cultivation (CWA §404(f)); exemptions for permitting of agricultural stormwater
discharges and return flows from irrigated agriculture; or exemptions for water transfers that do
not introduce pollutants into a waterbody. Nor would it change permitting processes.
In the third section of the proposed rule, the agencies add definitions of several terms, including
“tributary”; “significant nexus”; and “neighboring,” “floodplain,” and “riparian” as components
Congressional Research Service
5

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

of the existing term “adjacent.” The terms “adjacent” and “wetland” are not redefined in the
proposed rule. (See Table 1.)
EPA and the Corps believe that the proposed definitions of these terms are fully consistent with
long-standing practice and historical implementation of CWA programs and that they are
scientifically based.15 Nevertheless, because definitions often are key to interpreting statutory law
and regulations, some stakeholder groups have criticized the new definitions, suggesting that they
would enable broader assertion of CWA jurisdiction than is consistent with law and science.
Some critical attention has focused, for example, on the term “tributary,” previously defined in
guidance but not in regulation. As noted above, tributaries are per se jurisdictional under the
proposal, which defines the term to mean a water that is physically characterized by the presence
of a bed and banks and ordinary high water mark (as currently defined at 33 C.F.R. §328.3(e))
and which contributes flow, either directly or through another water, to a jurisdictional water. In
addition, under the proposal, wetlands, lakes, and ponds are tributaries—even if they lack a bed
and banks or ordinary high water mark—if they contribute flow, either directly or through another
water, to a jurisdictional water. Further, under the proposed definition, a water that otherwise
qualifies as a tributary does not lose its status as a tributary if, for any length, there are one or
more manmade breaks (e.g., dams) or natural breaks (e.g., debris piles), so long as a bed and
banks and an ordinary high water mark can be identified upstream of the break.16 Many
stakeholders assert that several of the defined terms in the proposal are confusing, and further that
the proposed rule fails to define terms such as “upland,” “gullies,” and “rills,” which they believe
need to be clarified.
Finally, the proposed rule includes two appendixes. One is an abbreviated, but lengthy, version of
the scientific assessment document still under review by EPA’s Science Advisory Board, plus
additional detail of the agencies’ reasoning concerning science in support of the proposed rule.
The other is an analysis of relevant case law.
Impacts of the Proposed Rule
The agencies acknowledge that the proposed rule would increase the categorical assertion of
CWA jurisdiction, when compared to a baseline of current practices under the existing regulations
and the 2003/2008 EPA-Corps guidance. This results in part from the agencies’ expressly
declaring some types of waters categorically jurisdictional and not requiring case-specific
evaluation of them (such as all waters adjacent to a jurisdictional water), and also by application
of definitions, which would give larger regulatory context to some types of waters, such as
tributaries.
In changing the regulatory definition of “waters of the United States,” there may be instances in
which the CWA applies for the first time, and there also may be instances in which the CWA no
longer applies (i.e., as a result of exemptions and exclusions). The agencies intend that the rule
will result in less ambiguity about whether the CWA applies.
The agencies believe that the proposed rule does not protect any new types of waters that have
not been protected historically and that it does not exceed the CWA’s coverage. That is, while it

15 79 Federal Register 22202, 22207.
16 79 Federal Register 22199.
Congressional Research Service
6

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

would enlarge categorical jurisdiction beyond that under the 2003 and 2008 EPA-Corps guidance,
which the agencies believe was narrower than is justified by science and the law, they believe that
it would not enlarge jurisdiction beyond what is consistent with the Supreme Court’s narrow
reading of jurisdiction. Others may disagree. Many stakeholders are concerned with what changes
the proposed rule will make, how much additional waters will be considered categorically
jurisdictional, and what additional costs will result.
The agencies’ proposed categorical assertion of waters that are jurisdictional, compared to
existing regulation and current practice, does not identify specific waters that will be found to be
jurisdictional—that is, this or that particular stream or pond—but the proposed rule attempts to
draw more of a bright line of CWA jurisdiction than in the past.
In an Economic Analysis document accompanying the proposed rule, EPA and the Corps estimate
that, overall, approximately 3% more acreage of wetlands and stream miles would additionally be
subject to CWA jurisdiction as a result of the proposed rule, compared with current field practice
under the 2008 guidance, and thus subject to CWA requirements. The estimated increase includes
about 17% of “other waters” (discussed above) that were not jurisdictional under the guidance, as
well as the result of assuming that all tributary streams and adjacent wetlands are jurisdictional.17
The agencies further estimate that 5% less wetland acreage and stream miles would be
determined to be jurisdictional under the proposal than were jurisdictional prior to the Supreme
Court’s SWANCC and Rapanos rulings.18
According to the analysis, costs to regulated entities and governments (federal, state, and local)
are likely to increase as a result of the proposal. Indirect costs would result from additional permit
application expenses (for CWA Section 404 permitting, stormwater permitting for construction
and development activities, and permitting of pesticide discharges and confined animal feeding
operations [CAFOs] for discharges to waters that would now be determined jurisdictional) and
additional requirements for oil storage and production facilities needing to develop and
implement spill prevention, control and countermeasure (SPCC) plans. Federal and state
governments would likely experience about $1 million annually in additional costs to administer
and process permits. Other costs would likely include compensatory mitigation requirements for
permit impacts (if applicable), affecting land developers and state and local governments. In all,
the agencies estimate that incremental costs associated with the rule range from $162 million to
$279 million per year.
The Section 404 program would see the greatest impact as a result of broader assertion of CWA
jurisdiction. Most of the projected costs are likely to affect landowners and development
companies, state and local governments investing in infrastructure, and industries involved in
resource extraction.19
The agencies believe that indirect benefits accruing from the proposed rule include the value of
ecosystem services provided by the waters and wetlands protected as a result of CWA

17 U.S. Environmental Protection Agency and U.S. Army Corps of Engineers, Economic Analysis of Proposed Revised
Definition of Waters of the United States
, March 2014, http://www2.epa.gov/uswaters/economic-analysis-proposed-
revised-definition-waters-united-states, p. 12.
18 Remarks of Jo-Ellen Darcy, Assistant Secretary of the Army (Civil Works), before the House Transportation and
Infrastructure Committee, Subcommittee on Water Resources and Environment, June 11, 2014.
19 Ibid., p. 32.
Congressional Research Service
7

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

requirements, such as habitat for aquatic and other species, support for recreational fishing and
hunting, and flood protection. Other benefits would include government savings on enforcement
expenses, because the rule is intended to provide greater regulatory certainty, thus reducing the
need for government enforcement. Business and government may also achieve savings from
reduced uncertainty concerning where CWA jurisdiction applies, they believe. In all, the agencies
estimate that benefits of the proposed rule range from $318 million to $514 million per year.
However, they note that “there is uncertainty and limitations associated with the results,” due to
data and information gaps, as well as analytic challenges. The analysis does not quantify all
possible costs and benefits, and values are meant to be illustrative, not definitive.20 Overall, they
conclude that benefits would exceed costs.
Unclear for now is a question of the extent to which case law construing the existing
administrative definition of “waters of the United States” will continue to apply. Some of that
case law has been in place for more than 35 years. The preamble to the proposed rule does not
address this issue.
Concerns of Agriculture and Local Governments
The agriculture sector has been vigorous in criticizing and challenging EPA regulatory actions
that may affect the sector’s operations, making potential impacts of the proposed rule on
agriculture a likely focus of controversy. One of the sector’s concerns about a new “waters of the
United States” rule has been whether it would modify existing statutory provisions that exempt
“normal farming and ranching” practices from dredge and fill permitting or others that exclude
certain agricultural discharges, such as irrigation return flow and stormwater runoff, from all
CWA permitting. As described above, the proposed rule makes no change and does not affect
these exemptions, which are self-implementing. An EPA fact sheet discusses the continued
exclusions and exemptions.21
In addition, simultaneous with proposing the rule, EPA and the Corps issued an interpretive rule
that identifies 56 conservation practices approved by the U.S. Department of Agriculture’s
Natural Resources Conservation Service (NRCS) that additionally qualify for exemption under
the CWA Section 404(f)(1)(A) exclusion of “normal farming and ranching” activities from
Section 404 permit requirements and do not require determination whether the discharge involves
a “water of the United States.” The 56, which are a subset of all NRCS conservation practices, are
practices such as stream crossings and wetland restoration that take place in aquatic, riparian, or
wetland environments. Through this interpretive rule, the agencies intend to resolve uncertainties
about “normal farming” activities that are exempt from permitting when these conservation
practices are used. In other words, effective immediately, producers who utilize any of the 56
identified practices according to NRCS technical standards need not seek a determination of
CWA jurisdiction and need not seek a CWA permit. The three agencies also have signed a
Memorandum of Understanding detailing implementation of the interpretive rule and identifying
a process for reviewing and updating the list of qualifying NRCS conservation practices.

20 Ibid., pp. 21-22, 32.
21 See http://www2.epa.gov/sites/production/files/2014-03/documents/cwa_ag_exclusions_exemptions.pdf. Comments
submitted to the docket for the interpretive rule (Docket ID No. EPA-HQ-OW-2013-0820) are available at
http://www.regulations.gov.
Congressional Research Service
8

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Although the interpretive rule is already in effect, EPA and the Corps accepted public comment
until July 7, 2014.22
The interpretive rule is intended to clarify agricultural practices that are exempt from CWA
Section 404 permitting. Nevertheless, confusion remains about many issues, including NRCS’s
role in providing technical assistance to farmers with respect to 404 permitting. Public comments
submitted on the interpretive rule are uniformly critical—including comments submitted by
agriculture stakeholder groups, environmental groups, and some state environmental agencies.
Agriculture groups argue that it is procedurally flawed, because it will have substantive impact on
farmers, and thus is subject to notice-and-comment rulemaking procedures under the
Administrative Procedure Act. Many also argue that the interpretive rule has narrowed the CWA
404(f)(1)(A) statutory exemptions, because the practices listed in the rule already were excluded
from Section 404, but now must comply with NRCS standards, resulting in a disincentive to
conservation. EPA and the Corps respond that the intent of the interpretive rule to expand, not
contract, the number of exempted activities may be unclear. On the other hand, environmental
groups and some state environmental agencies are critical of the interpretive rule for different
reasons. They contend that it will exempt activities from permitting that are not truly associated
with ongoing farming and that the rule is thus too broad. Some of the listed practices, such as
stream crossings, can have significant harmful impacts on water quality and result in violations of
state water quality standards, they say.
EPA and Corps officials now acknowledge that the interpretive rule does not appear to have had
the intended benefits of clarifying agricultural exemptions, and they have said that the agencies
and U.S. Department of Agriculture (USDA) are weighing alternatives to the rule. No decisions
have been made.
Some local governments have also criticized the proposed rule. In particular, the National
Association of Counties (NACo) argues that counties and other local governments would be
affected by the proposed rule in the arena of ditches. NACo points out that local governments
own and maintain public infrastructure including roadside ditches, flood control channels, and
stormwater management structures. Because the proposed rule would define some ditches as
“waters of the United States” if they meet certain conditions (i.e., if they are defined as
tributaries), NACo contends that the proposal potentially increases the number of county-owned
ditches under federal jurisdiction. Permit requirements are not an issue, NACo says, but
permitting can be time-consuming and expensive. EPA and Corps officials believe that the
proposed exclusion of most ditches (see “Exclusions and Definitions”) actually decreases federal
jurisdiction over ditches, but the issue remains controversial.

22 Department of Defense, Department of the Army, Corps of Engineers, and Environmental Protection Agency,
“Notice of Availability Regarding the Exemption From Permitting Under Section 404(f)(1)(A) of the Clean Water Act
to Certain Agricultural Conservation Practices,” 79 Federal Register 22276, April 21, 2014.The list of practices, the
Memorandum of Understanding, and the interpretive rule are available at http://water.epa.gov/lawsregs/guidance/
wetlands/agriculture.cfm. USDA had no formal role in developing the Corps-EPA proposed rule, but it was among the
federal agencies commenting on it during interagency review.
Congressional Research Service
9

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Conclusion and Legislative Responses
The Corps and EPA accepted public comment on the proposed rule until November 14, 2014. As
noted above, the agencies pledge that a final rule will not be promulgated before completion of
EPA’s scientific assessment report, which is expected to occur early in 2015.
The EPA Administrator stated at a congressional hearing that it generally takes about one year to
finalize a rule. Complex and controversial rules can take much longer from proposal to
promulgation. According to EPA’s “Regulatory Gateway,” the agencies anticipate that a final rule
will be promulgated by April 2015, but that projected date could slip, depending on review of the
more than 400,000 comments that were submitted and need for changes to the rule as proposed.23
A final rule could differ significantly from the proposal in addressing critiques and commenters’
calls for clarification and substantive change.
Once a rule is finalized, legal challenges are likely, possibly delaying implementation of any rule
for years. New regulations may clarify many current questions, but they are unlikely to please all
of the competing interests, as one environmental advocate observed.
However, a rulemaking would only benefit wetlands if it did not reduce the jurisdiction
offered by current regulations and if the Administration remained faithful to sound science.
If politics were to trump science in the rulemaking process, the likelihood of such a
protective rule would not be promising. Also, rules are subject to legal challenge and can be
tied up in court for years before they are implemented.24
Congressional interest in the proposed rule has been strong since the agencies’ announcement on
March 25. Public and agency witnesses have discussed the proposal at several hearings (House
Agriculture Committee, House Natural Resources, House Government Reform and Oversight
Committee, House Small Business Committee, House Science Committee, and House
Transportation and Infrastructure Committee).
Legislation addressing the proposal has been introduced. H.R. 5078 would prohibit the Corps or
EPA from finalizing the proposed “waters” rule or using that proposal or similar proposed rule or
guidance as the basis of any rulemaking on the scope of CWA jurisdiction, and it would require
withdrawal of the interpretive rule. It also would direct the Corps and EPA to consult with state
and local officials on CWA jurisdiction issues and develop a report on results of such
consultation. By a 262-152 vote, the House passed this bill on September 9.
Other bills have been introduced, as well. H.R. 4923, FY2015 Energy and Water Appropriations
act, passed by the House on July 10, includes a provision that would bar the Corps from
developing, adopting, implementing, or enforcing any change to rules or guidance pertaining to
the CWA definition of “waters of the United States.” Also, the FY2015 Interior and Environment
Appropriations Act, funding EPA (H.R. 5171), contains a provision to similarly block funding for
EPA to act on the “waters” rule. The House Appropriations Committee approved this bill in July.
S. 2496, like H.R. 5078, would prohibit the Corps or EPA from finalizing the proposed “waters”

23 See EPA Regulatory Development and Retrospective Review Tracker, http://yosemite.epa.gov/opei/RuleGate.nsf/
byRIN/2040-AF30.
24 James Murphy, “Rapanos v. United States: Wading Through Murky Waters,” National Wetlands Newsletter, vol. 28,
no. 5, September-October 2006, p. 19.
Congressional Research Service
10

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

rule or using that proposal or similar proposed rule or guidance as the basis of any rulemaking on
the scope of CWA jurisdiction. H.R. 5071 would require the agencies to withdraw the interpretive
rule on agricultural exemptions and direct that all soil and water conservation practices shall be
treated as “normal farming, ranching, and forestry” activities for purposes of CWA Section
404(f)(1)(A).

Congressional Research Service
11


Table 1. Comparison of “Definition of Waters of the United States” Regulatory Language
Current Regulatory Language and Proposed Rule Published in the Federal Register April 21, 2014
Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
(a) The term waters of the United States means
(a) For purposes of al sections of the Clean Water Act,
33 U.S.C. 1251 et seq. and its implementing regulations,
subject to the exclusions in subsection (b) of this
section, the term “waters of the United States” means:
(1) Al waters which are currently used, or were used
(1) All waters which are currently used, were used in
These waters are often referred to as “traditional
in the past, or may be susceptible to use in interstate or the past, or may be susceptible to use in interstate or
navigable waters” (TNWs), which include but are not
foreign commerce, including all waters which are
foreign commerce, including all waters which are
limited to the “navigable waters of the United States”
subject to the ebb and flow of the tide;
subject to the ebb and flow of the tide;
within the meaning of Section 10 of the Rivers and
Harbors Act of 1899. No change from the existing rule.
(2) All interstate waters including interstate wetlands;
(2) All interstate waters, including interstate wetlands;
These waters 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. No change
from the existing rule. Interstate waters would continue
to be “waters of the United States” even if they are not
navigable in fact and do not connect to such waters.
(3) All other waters such as intrastate lakes, rivers,
(7) On a case-specific basis, other waters, including
In the existing rule, there is a non-exclusive list of the
streams (including intermittent streams), mudflats,
wetlands, provided that those waters alone, or in
types of “other waters” which may be found to be
sandflats, wetlands, sloughs, prairie potholes, wet
combination with other similarly situated waters,
“waters of the U.S.” The existing description is omitted
meadows, playa lakes, or natural ponds, the use,
including wetlands, located in the same region, have a
under the proposal as unnecessary and confusing
degradation or destruction of which could affect
significant nexus to a water identified in paragraphs
because it includes some waters that would be
interstate or foreign commerce including any such
(a)(1) through (3) of this section.
jurisdictional under one of the categories of waters that
waters:
are jurisdictional by rule under the proposal (for
example, an intermittent stream that meets the
definition of tributary). Under the proposed rule,
“other waters” are not jurisdictional as a single
category but require a case-specific analysis of a
significant nexus to a traditional navigable water, an
interstate water, or the territorial seas. They may be
evaluated either individually, or as a group of waters
where they are determined to be similarly situated in a
region. “In the region” means the watershed that drains
to the nearest traditional navigable water, interstate
CRS-12


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
water, or the territorial seas through a single point of
entry. How other waters are aggregated for a case-
specific significant nexus analysis depends on the
functions they perform and their spatial arrangement
within the region or watershed. It is the landscape
position within the watershed that is the determinative
factor for the analysis, which will focus on the degree
to which the functions provided by the other waters
affect the chemical, physical, or biological integrity of
(a)(1) through (a)(3) waters.
Current rule asserts jurisdiction more broadly than
what is proposed; the proposal deletes language
requiring that an “other water” be one “the use,
degradation or destruction of which could affect
interstate commerce” and replaces it with requirement
that the “other water” meet the significant nexus
standard. The agencies consider this a substantial
change from the current rule.
(i) Which are or could be used by interstate or

Specific examples are omitted in the proposed rule as
foreign travelers for recreational or other purposes; or
unnecessary. The agencies say that the listing has led to
confusion where it has been incorrectly read as an
exclusive list.
(ii) From which fish or shellfish are or could be taken


and sold in interstate or foreign commerce; or
(iii) Which are used or could be used for industrial


purpose by industries in interstate commerce;
(4) All impoundments of waters otherwise defined as
(4) All impoundments of waters identified in paragraphs
Impoundments of a traditional navigable water,
waters of the United States under the definition;
(a)(1) through (3) and (5) of this section;
interstate water, the territorial seas, or a tributary are
jurisdictional by rule.
As a matter of policy and law, impoundments do not
de-federalize a water, even where there is no longer
flow below the impoundment. That is, damming or
impounding a water of the United States does not make
the water non-jurisdictional.
(5) Tributaries of waters identified in paragraphs (a)(1)
(5) All tributaries of waters identified in paragraphs
Tributaries, as defined in the proposed rule, of a
CRS-13


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
through (4) of this section;
(a)(1) through (4) of this section;
traditional navigable water, interstate water, the
territorial seas, or an impoundment would be
jurisdictional by rule.
Unless excluded under subsection (b) of the proposed
rule, any water that meets the proposed definition of
tributary is a water of the United States, whether it is
perennial, intermittent, or ephemeral. The water may
contribute flow directly or may contribute flow to
another water or waters that eventually flow into a
jurisdictional water. The tributary must drain, or be
part of a network of tributaries that drain, into an (a)(1)
through (a)(4) water.
“Tributary” is defined below.
(6) The territorial seas;
(3) The territorial seas;
Jurisdictional by rule; no change from the existing rule.
(7) Wetlands adjacent to waters (other than waters
(6) All waters, including wetlands, adjacent to a water
All waters, including wetlands, adjacent to a traditional
that are themselves wetlands) identified in paragraphs
identified in paragraphs (a)(1) through (5) of this
navigable water, interstate water, the territorial seas,
(a)(1) through (6) of this section.
section; and
impoundment, or tributary would be jurisdictional by
rule. Under the proposed rule, wetlands, ponds, lakes,
and similar waterbodies that are adjacent to traditional
navigable waters, interstate waters, and the territorial
seas, as well as waters and wetlands adjacent to other
jurisdictional waters such as tributaries and
impoundments, would be jurisdictional by rule.

(b) The following are not “waters of the United

States”
(8) Waters of the United States do not include prior
(2) Prior converted cropland. Notwithstanding the
No change proposed.
converted cropland.c Notwithstanding the
determination of an area’s status as prior converted
determination of an area’s status as prior converted
cropland by any other federal agency, for the purposes
cropland by any other Federal agency, for the purposes
of the Clean Water Act, the final authority regarding
of the Clean Water Act, the final authority regarding
Clean Water Act jurisdiction remains with EPA.
Clean Water Act jurisdiction remains with EPA.
Waste treatment systems, including treatment ponds or (1) Waste treatment systems, including treatment
The agencies do not believe that omitting the
lagoons designed to meet the requirements of CWA
ponds or lagoons, designed to meet the requirements
parenthetical reference to 40 C.F.R. 423.11(m) is a
(other than cooling ponds as defined in 40 C.F.R.
of the Clean Water Act.
change in substance to the waste treatment exclusion
CRS-14


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
423.11(m) which also meet the criteria of this
or how it is applied.
definition) are not waters of the United States.d

(3) Ditches that are excavated wholly in uplands, drain
Proposed rule would codify long-standing practice and
only uplands or non-jurisdictional waters, and have less
guidance (including 1986 and 1988 preamble language),
than perennial flow.
which has been to exclude these waters from
jurisdiction.
Excluded ditches must be dug only in uplands, drain
only uplands, and have ephemeral or intermittent flow.
Ditches in uplands would need to have perennial flow
to be jurisdictional, even if they connect to downstream
waters. Water that only stands or pools in a ditch is
not considered perennial flow and, therefore, any such
upland ditch would not be subject to regulation.

(4) Ditches that do not contribute flow, either directly
Proposed rule would codify long-standing practice and
or through another water, to a water identified in
guidance (including 1986 and 1988 preamble language),
paragraphs (a)(1) through (4) of this section.
which has been to exclude these waters from
jurisdiction. These waters would not be jurisdictional by
rule.
Ditches that do not contribute flow, directly or
indirectly, to the tributary system of a traditional
navigable water, interstate water, impoundment, or the
territorial seas are not “waters of the United States,”
even if the ditch has a perennial flow.
Other ditches, if they meet the new proposed definition
of “tributary” and contribute flow, directly or indirectly,
to a jurisdictional water (see “tributary” definition
below) would continue to be waters of the United
States.
Ditches may function as point sources that discharge
pol utants, thus subject to CWA Section 402.

(5) The following features: (i) Artificially irrigated areas
Proposed rule would codify long-standing practice and
that would revert to upland should application of
guidance (including 1986 and 1988 preamble language),
irrigation water to that area cease; (ii) artificial lakes or
which has been to exclude these waters from
ponds created by excavating and/or diking dry land and
jurisdiction. These waters would not be jurisdictional by
used exclusively for such purposes as stock watering,
rule.
CRS-15


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
irrigation, settling basins, or rice growing; (ii ) artificial
reflecting pools or swimming pools created by
excavating and/or diking dry land; (iv) small ornamental
waters created by excavating and/or diking dry land for
primarily aesthetic reasons; (v) water-filled depressions
created incidental to construction activity; (vi)
groundwater, including groundwater drained through
subsurface drainage systems; and (vii) gullies and rills
and non-wetland swales.

(c) Definitions—

(b) The term wetlands means those areas that are
(6) Wetlands: The term wetlands means those areas
No change proposed.
inundated or saturated by surface or ground water at a
that are inundated or saturated by surface or ground
frequency and duration sufficient to support, and that
water at a frequency and duration sufficient to support,
Wetlands are ecosystems that often occur at the edge
under normal circumstances do support, a prevalence
and that under normal circumstances do support, a
of aquatic (water, fresh or salty) or terrestrial (upland)
of vegetation typically adapted for life in saturated soil
prevalence of vegetation typically adapted for life in
systems. Wetlands typically represent transitional zones
conditions. Wetlands generally include swamps,
saturated soil conditions. Wetlands generally include
between aquatic and upland systems.
marshes, bogs, and similar areas.
swamps, marshes, bogs, and similar areas.
(c) The term adjacent means bordering, contiguous, or
(1) Adjacent: The term adjacent means bordering,
Current rule limits consideration of adjacency to
neighboring. Wetlands separated from other waters of
contiguous or neighboring. Waters, including wetlands,
wetlands. Proposed rule would change “adjacent
the United States by man-made dikes or barriers,
separated from other waters of the United States by
wetlands” to “adjacent waters” so that waterbodies
natural river berms, beach dunes and the like are
man-made dikes or barriers, natural river berms, beach
such as ponds and oxbow lakes [a U-shaped body of
‘‘adjacent wetlands.’’
dunes and the like are “adjacent waters.”
water formed when a wide meander from a river is cut
off to form a lake] as well as wetlands that are adjacent
to jurisdictional waters are “waters of the U.S.” by
regulation. The rule would include wetlands and other
waterbodies that meet the proposed definition of
adjacent, including “neighboring,” which is defined
separately. Adjacent waters are those that provide
similar functions which, together with functions provided
by tributaries to which they are adjacent
, have a significant
nexus to traditional navigable waters (TNWs),
interstate waters, and the territorial seas. “In the
aggregate, all adjacent waters have a significant nexus
with their downstream TNWs or interstate waters.”
The lateral limits of an adjacent water, other than
wetlands or tributaries, are determined by the presence
of an ordinary high water mark (OHWM) without the
CRS-16


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
need for a bed and banks. Deletion of parenthetical
phrase in the existing rule is intended to ensure that all
waters that meet the proposed definitions of “adjacent”
are “waters of the U.S.” regardless of whether or not
another adjacent water is located between those
waters and the tributary.
(d) The term high tide line means the line of intersection No change proposed

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 shel or debris on the
foreshore or berm, other physical markings or
characteristics, vegetation lines, tidal gages, or other
suitable means that delineate the general height reached
by a rising tide. The line encompasses spring high tides
and other high tides that occur with periodic frequency
but does not include storm surges in which there is a
departure from the normal or predicted reach of the
tide due to the piling up of water against a coast by
strong winds such as those accompanying a hurricane
or other intense storm.
(e) The term ordinary high water mark means that line on No change proposed

the shore established by the fluctuations of water and
indicated by physical characteristics such as clear,
natural line impressed on the bank, shelving, changes in
the character of soil, destruction of terrestrial
vegetation, the presence of litter and debris, or other
appropriate means that consider the characteristics of
the surrounding area.
(f) The term tidal waters means those waters that rise
No change proposed

and fall in a predictable and measurable rhythm or cycle
due to the gravitational pulls of the moon and sun. Tidal
waters end where the rise and fall of the water surface
can no longer be practical y measured in a predictable
rhythm due to masking by hydrologic, wind, or other
effects.
CRS-17


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
(2)
Neighboring: The term neighboring, for purposes
Waters, including wetlands, that are located within the
of the term “adjacent” in this section, includes waters
riparian area or floodplain of an (a)(1) through (a)(5)
located within the riparian area or floodplain of a water
water would be jurisdictional without a case-specific
identified in paragraphs (a)(1) through (a)(5) of this
significant nexus analysis. Even if separated from such a
section, or waters with a surface or shallow subsurface
water by natural or man-made features (e.g., a berm),
hydrologic connection to such a jurisdictional water.
the water would be adjacent and thus jurisdictional.
(3)
Riparian area: The term riparian area means an
The term “riparian area” is used to help identify waters,
area bordering a water where surface or subsurface
including wetlands, that may be “adjacent” and would,
hydrology influence the ecological processes and plant
therefore, be “waters of the United States” under the
and animal community structure in that area. Riparian
proposed rule. No uplands located in “riparian areas”
areas are transitional areas between aquatic and
can ever be “waters of the United States.”
terrestrial ecosystems that influence the exchange of
energy and materials between those ecosystems.
(4)
Floodplain: The term floodplain means an area
The term “floodplain” is used to help identify waters,
bordering inland or coastal waters that was formed by
including wetlands, that may be “adjacent” and would,
sediment deposition from such water under present
therefore, be “waters of the United States” under the
climatic conditions and is inundated during periods of
proposed rule. No uplands located in “floodplains” can
moderate to high water flows.
ever be “waters of the United States.”
(5)
Tributary: The term tributary means a waterbody
This term has not previously been defined in any
physically characterized by the presence of a bed and
regulation or preamble.
banks and ordinary high water mark, as defined at 33
C.F.R. §328.3(e), which contributes flow, either directly
Bed and banks and ordinary high water mark (OHWM)
or through another water, to a water identified in
are features that generally are physical indicators of
paragraphs (a)(1) through (4) of this section. In addition, flow. OHWM generally defines the lateral limits of a
wetlands, lakes, and ponds are tributaries (even if they
water. In many tributaries, the bed is that part of the
lack a bed and banks or ordinary high water mark) if
channel below the OHWM, and the banks often extend
they contribute flow, either directly or through another above the OHWM.
water to a water identified in paragraphs (a)(1) through
Wetland tributaries are wetlands that are located
(3) of this section. A water that otherwise qualifies as a
within the stream channel itself or that form the start
tributary under this definition does not lose its status as of the stream channel.
a tributary if, for any length, there are one or more
man-made breaks (such as bridges, culverts, pipes, or
Man-altered and man-made tributaries perform many of
dams) or one or more natural breaks (such as wetlands
the same functions as natural tributaries and provide
at the head of or along the run of a stream, debris piles, connectivity between streams and downstream rivers.
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
CRS-18


Current Regulatory Languagea Proposed
Regulatory
Language
Commentsb
tributary, including wetlands, can be a natural, man-
altered, or man-made waterbody and includes waters
such as rivers, streams, lakes, ponds, impoundments,
canals, and ditches not excluded in paragraph (b)(3) or
(4) of this section.
(7)
Significant nexus: The term significant nexus
A significant nexus analysis may be based on a particular
means that a water, including wetlands, either alone or
water alone or on the effect that the water has in
in combination with other similarly situated waters in
combination with other similarly situated waters in the
the region (i.e., the watershed that drains to a water
region. “Region” means the watershed that drains to a
identified in paragraphs (a)(1) through (3) of this
water identified in (a)(1) through (a)(3) through a single
section), significantly affects the chemical, physical or
point of entry.
biological integrity of a water identified in paragraphs
(a)(1) through (3) of this section. For an effect to be
Proposed rule adopts the concept of aggregating certain
significant, it must be more than speculative or
waters to determine whether they meet the “alone or
insubstantial. Other waters, including wetlands, are
in combination with similarly situated waters” test of
similarly situated when they perform similar functions
Justice Kennedy. Waters must perform similar functions
and are located sufficiently close together or close to a
and be located sufficiently close together or close to a
“water of the U.S.” so that they can be evaluated as a
traditional navigable water, interstate water, or the
single landscape unit with regard to their effect on the
territorial seas so that they can be evaluated as a single
chemical, physical, or biological integrity of a water
landscape unit with regard to their effects. Examining
identified in paragraphs (a)(1) through (3) of this
both functionality and proximity limits the “other
section.
waters” that can be aggregated for purposes of
determining jurisdiction.
Functions that might demonstrate significant nexus
include sediment trapping and retention of flood
waters. A hydrologic connection is not necessary,
because the function may be demonstrated even in the
absence of a connection (e.g., pol utant trapping).
Source: Prepared by CRS.
Notes: The proposed rule that was announced on March 25, 2014, was published in the Federal Register on April 21, 2014 (79 Federal Register 22188-22274).
a. 33 C.F.R. 328.3, 40 C.F.R. 122.2, 40 C.F.R. 230.3, and 40 C.F.R. 232.2 (definition of “waters of the United States”). The term “navigable waters” is defined at 40
C.F.R. 110.1 (Discharge of Oil); 40 C.F.R. 112.2 (Oil Pollution Prevention); 40 C.F.R. 116.3 (Designation of Hazardous Substance); 40 C.F.R. 117.1(i) (Determination
of Reportable Quantities for Hazardous Substances); 40 C.F.R. 300.5 and Appendix E 1.5 to Part 300 (National Oil and Hazardous Substances Pollution Contingency
Plan); and 40 C.F.R. 302.3 (Designation, Reportable Quantities, and Notification).
b. Comments in this table are drawn in large part from the preamble to the proposed rule.
CRS-19


c. The term “prior converted cropland” is included in the U.S. Department of Agriculture’s administrative definition of the term “wetland” (see 7 C.F.R. 12.2).
d. A definition of “waste treatment system” is found in EPA regulations (35 C.F.R. 35.905): “Complete waste treatment system. A complete waste treatment system
consists of all of the treatment works necessary to meet the requirements of title III of the Act, involved in (a) The transport of waste waters from individual homes
or buildings to a plant or facility where treatment of the waste water is accomplished; (b) the treatment of the waste waters to remove pollutants; and (c) the
ultimate disposal, including recycling or reuse, of the treated waste waters and residues which result from the treatment process. One complete waste treatment
system would, normally, include one treatment plant or facility, but also includes two or more connected or integrated treatment plants or facilities.”

CRS-20

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

Appendix. EPA’s Draft Connectivity Report and
Review by the Science Advisory Board

In September 2013, EPA released a draft report that reviews and synthesizes the peer-reviewed
scientific literature on the connectivity or isolation of streams and wetlands relative to large water
bodies such as rivers, lakes, estuaries, and oceans. The purpose of the review, according to EPA,
is to summarize current understanding about these connections, the factors that influence them,
and mechanisms by which connected waters affect the function or condition of downstream
waters.25 The focus of the draft report, which was prepared by EPA’s Office of Research and
Development, is on small or temporary non-tidal streams, wetlands, and open waters. Based on
the reviewed literature, it makes certain findings.
• All tributary streams, including perennial, intermittent, and ephemeral streams,
are physically, chemically, and biologically connected to downstream rivers.
• Wetlands and open waters in riparian areas and floodplains also are physically,
chemically, and biologically connected with rivers and serve an important role in
the integrity of downstream waters. In these types of wetlands, water-borne
materials can be transported from the wetland to the river network and vice versa
(e.g., water from a stream flows into and affects the wetland).
• Wetlands and open waters where water only flows from the wetland or water to a
river network, (i.e., non-floodplain waters and wetlands that lack surface water
inlets) such as many prairie potholes, vernal pools, and playa lakes, provide
numerous functions that can benefit downstream water quality and integrity.
However, because such wetlands occur on a gradient of connectivity, it is
difficult to generalize, from the literature alone, about their effects on
downstream waters or to generalize about the degree of connectivity (absolute or
relative).
EPA asked its Science Advisory Board (SAB) to review the draft report and to comment on
whether its conclusions and findings are supported by the available science.26 The EPA draft
report is not intended as a policy document—it does not reference either the Scalia plurality or
Kennedy tests in Rapanos, nor does it address legal standards for CWA jurisdiction. Nevertheless,
the report is important to EPA and the Corps because, when finalized, it will provide a scientific
basis needed to clarify CWA jurisdiction and, thus, to inform the “waters of the United States”
rulemaking.27 The SAB convened a special panel of scientists to review the draft synthesis
document. This ad hoc panel held meetings and teleconferences from late 2013 through mid-2014
and prepared a report with recommendations.

25 U.S. Environmental Protection Agency, Office of Research and Development, Connectivity of Streams and Wetlands
to Downstream Waters: A Review and Synthesis of the Scientific Evidence
, External Review Draft, EPA/600/R-11-
098B, September 2013, http://yosemite.epa.gov/sab/sabproduct.nsf/0/7724357376745F48852579E60043E88C/$File/
WOUS_ERD2_Sep2013.pdf.
26 The SAB was established pursuant to the Environmental Research, Development, and Demonstration Authorization
Act (42 U.S.C. 4365) to provide independent scientific and technical advice to the EPA Administrator on the technical
basis for agency positions and regulations.
27 See U.S. Environmental Protection Agency, “Clean Water Act Definition of ‘Waters of the United States,’”
http://water.epa.gov/lawsregs/guidance/wetlands/CWAwaters.cfm.
Congressional Research Service
21

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

In its report,28 the SAB ad hoc panel found strong support for the first two of EPA’s major
conclusions in the synthesis document and concluded that it is a thorough and technically
accurate review of the literature on the connectivity of streams and wetlands to downstream
waters. In particular, the panel agreed with EPA’s conclusions that ephemeral, intermittent, and
perennial streams exert a strong influence on the character and functioning of downstream waters
and that tributary streams are connected to downstream waters. Further, the panel agreed with
EPA that streams and wetlands in floodplain settings are physically, chemically, and/or
biologically connected to downstream navigable waters.
The ad hoc panel found that the peer-reviewed literature supports EPA’s conclusions in the
synthesis report that connectivity occurs along a gradient or continuum between fully connected
and completely isolated, with a transition in between that varies case-by-case. However, the panel
concluded that the EPA report often refers to connectivity as though it is a binary property
(connected versus not connected). Instead, the panel found that there are four dimensions to
connectivity (longitudinal, lateral, vertical, and temporal). It is technically more accurate to state
that the consequences to downstream waters are determined by variation in the frequency,
duration, predictability, and magnitude of connections and that relatively low levels of
connectivity can be meaningful in terms of impacts.
The ad hoc panel disagreed with EPA’s third major conclusion, that it is difficult to generalize
from currently available literature the degree of connectivity or the downstream effects of non-
floodplain waters and wetlands that are not connected to a river network through surface or
shallow subsurface water. The SAB panel found that “the scientific literature supports a more
definitive statement that reflects how numerous functions of non-floodplain wetlands sustain the
physical, chemical, and/or biological integrity of downstream waters, although the degree of
connectivity can vary widely.”29 The report would be strengthened, the ad hoc panel said, if it
framed the discussion of connectivity gradients and their consequences as a function of the
magnitude, duration, and frequency of connectivity pathways among wetlands and downstream
waters and if it quantified each connection, to the degree possible, while identifying research and
data gaps. The panel found that at sufficiently large spatial and temporal scales, all waters and
wetlands are connected. More important are the degree of connection (e.g., frequency, duration)
and the extent to which those connections affect the chemical, physical, and biological integrity
of downstream waters. Within non-floodplain wetlands, the degree of connectivity and
implications for integrity of downstream waters vary considerably.
The EPA Report suggests that determining the connectedness of each non-floodplain
wetland must be done on a case-by-case basis. The SAB suggests that the vast majority of
non-floodplain wetlands can be classified with respect to some degree of hydrologic,
chemical or biological connections to downstream waters; however, some hydrologically and
spatially disconnected wetlands may need to be considered on a case-by-case basis. The
challenge for the EPA is to describe the hierarchy of decisions and the tools necessary to
assess the degree of connection necessary to warrant case-by-case analysis.30

28 Science Advisory Board, “SAB Review of the Draft EPA Report Connectivity of Streams and Wetlands to
Downstream Waters: A Review and Synthesis of the Scientific Evidence
, Draft Report,” August 11, 2014, 105 p.,
http://yosemite.epa.gov/sab/SABPRODUCT.NSF/81e39f4c09954fcb85256ead006be86e/
212BB1480331835285257D350041A1C0/$File/
SAB+Connectivity+Panel+Draft+Report_8_11_14_%28quality+review+draft%29.pdf.
29 Ibid., pp. 1, 6.
30 Ibid., p. 56.
Congressional Research Service
22

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

The full, chartered SAB reviewed the ad hoc panel’s report in September 2014. SAB members
said that the panel’s review of the draft EPA study was technically accurate and clear and that it
accurately established linkages between streams, wetlands, and downstream waters. The SAB
members asked for several minor revisions to the ad hoc panel’s report, which were reflected in
an October 17, 2014, letter to the EPA Administrator with its findings and recommendations
regarding the synthesis document.31
In addition to advising the EPA Administrator on the “connectivity” report, the chartered SAB
agreed to review the adequacy of the scientific and technical basis of the proposed “waters of the
United States” rule. As input to the SAB, members of the ad hoc panel that reviewed the
“connectivity” report subsequently reviewed the proposed. (Unlike their formal review of the
“connectivity” report, the panel did not seek consensus on their views of the scientific basis of the
proposed CWA rule.) The ad hoc panel sought to bring their scientific expertise to questions of
law and policy in the proposed rule, but at the same time, members’ comments highlighted some
difficulties in doing so.
Members of the ad hoc panel found general agreement that, based on available science, tributaries
and adjacent waters and wetlands are appropriately jurisdictional under the proposed rule. They
generally agreed that from a scientist’s perspective, key terms need clarification and better
definition, including “significant,” “similarly situated,” “floodplain,” and “adjacent.” The
definition of “adjacent” is important, for example, because where “adjacent” is determined then
determines the beginning of “other waters” that require case-by-case evaluation of jurisdiction.
Several said that the proposed definition of “tributary” should be broader, that is, that it should
specify a bed and bank (as proposed) and in some cases an ordinary high water mark (but not in
all cases, as proposed). Several referred to the panel’s review of the “connectivity” report and said
that the rule should equally reflect the importance of chemical and biological connections
between waters, as well as hydrological connections, in determining significant nexus, as the
panel’s report did. Similarly, several noted the emphasis in the panel’s report on connections
resulting from groundwater pathways—shallow subsurface, shallow or deep groundwater—in
questioning the categorical exclusion of federal jurisdiction over groundwater in the proposed
rule.32 Likewise, some on the panel said that the distinction between ditches that would and would
not be jurisdictional under the proposed rule is unclear and may not be adequately supported by
the science, although they recognized that the agencies may have policy reasons for doing so.
EPA and the Corps face the challenge of assessing how the rule as proposed, or possible revisions
to it, fully reflect science, law, and the statutory authority of the Clean Water Act.
The full chartered SAB also considered the ad hoc panel’s review of the proposed “waters of the
United States” rule in September, and it approved an advisory letter to be sent to the EPA
Administrator.33 The letter supports the categorical inclusion of all tributaries, including those

31 The October 17, 2014, letter and SAB final peer review of the draft “connectivity” report is available at
http://yosemite.epa.gov/sab/sabproduct.nsf/WebReportsLastFiveBOARD/AF1A28537854F8AB85257D74005003D2/
$File/EPA-SAB-15-001+unsigned.pdf.
32 In addition to uncertainty over the scope of CWA jurisdiction in general, court are split on the question of whether
EPA and the Corps may assert jurisdiction over groundwater connected to navigable waters. The statutory language is
ambiguous when discussing groundwater. See Anna Makowski, “Beneath the Surface of the Clean Water Act:
Exploring the Depth of the Act’s Jurisdictional Scope of Groundwater Pollution,” Oregon Law Review, vol. 91 (2012),
pp. 495-526.
33 The text of the SAB letter concerning the proposed rule is available at http://yosemite.epa.gov/sab/sabproduct.nsf/
(continued...)
Congressional Research Service
23

EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”

classified as intermittent and ephemeral. The letter also supports case-by-case consideration of
most “other waters,” but it finds that there is adequate scientific evident to support a
determination that certain types of waters in particular U.S. regions (e.g., prairie potholes, Texas
coastal prairie wetlands) could be categorically considered waters of the United States. In the
letter, the SAB urged EPA to reconsider the definition of tributaries, which the proposed rule
defines as having a bed, a bank, and an ordinary high water mark, because in the SAB’s
judgment, not all tributaries have ordinary high water marks. Finally, the letter disagrees with
certain categorical exclusions in the proposed rule, saying that science does not justify excluding
waters such as groundwater, ditches, gullies, rills, and non-wetland swales, because in many cases
they can be connected to jurisdictional waters or can be conduits for moving water between
jurisdictional waters.

Author Contact Information
Claudia Copeland
Specialist in Resources and Environmental Policy
ccopeland@crs.loc.gov, 7-7227


(...continued)
518D4909D94CB6E585257D6300767DD6/$File/EPA-SAB-14-007+unsigned.pdf.
Congressional Research Service
24