Rapanos v. United States

(Slip Opinion) OCTOBER TERM, 2005 1

Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
being done in connection with this case, at the time the opinion is issued.
The syllabus constitutes no part of the opinion of the Court but has been
prepared by the Reporter of Decisions for the convenience of the reader.
See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

RAPANOS ET UX., ET AL. v. UNITED STATES

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
THE SIXTH CIRCUIT

No. 04–1034. Argued February 21, 2006—Decided June 19, 2006*
As relevant here, the Clean Water Act (CWA or Act) makes it unlawful
to discharge dredged or fill material into “navigable waters” without
a permit, 33 U. S. C. §§1311(a), 1342(a), and defines “navigable wa
ters” as “the waters of the United States, including the territorial
seas,” §1362(7). The Army Corps of Engineers (Corps), which issues
permits for the discharge of dredged or fill material into navigable
waters, interprets “the waters of the United States” expansively to
include not only traditional navigable waters, 33 CFR §328.3(a)(1),
but also other defined waters, §328.3(a)(2), (3); “[t]ributaries” of such
waters, §328.3(a)(5); and wetlands “adjacent” to such waters and
tributaries, §328.3(a)(7). “[A]djacent” wetlands include those “border
ing, contiguous [to], or neighboring” waters of the United States even
when they are “separated from [such] waters . . . by man-made dikes
. . . and the like.” §328.3(c).
These cases involve four Michigan wetlands lying near ditches or
man-made drains that eventually empty into traditional navigable
waters. In No. 04–1034, the United States brought civil enforcement
proceedings against the Rapanos petitioners, who had backfilled
three of the areas without a permit. The District Court found federal
jurisdiction over the wetlands because they were adjacent to “waters
of the United States” and held petitioners liable for CWA violations.
Affirming, the Sixth Circuit found federal jurisdiction based on the
sites’ hydrologic connections to the nearby ditches or drains, or to
more remote navigable waters. In No. 04–1384, the Carabell peti
tioners were denied a permit to deposit fill in a wetland that was
——————
* Together with No. 04–1384, Carabell et al. v. United States Army
Corps of Engineers et al., also on certiorari to the same court.
2 RAPANOS v. UNITED STATES

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separated from a drainage ditch by an impermeable berm. The
Carabells sued, but the District Court found federal jurisdiction over
the site. Affirming, the Sixth Circuit held that the wetland was adja
cent to navigable waters.
Held: The judgments are vacated, and the cases are remanded.
No. 04–1034, 376 F. 3d 629, and No. 04–1384, 391 F. 3d 704, vacated
and remanded.
JUSTICE SCALIA, joined by THE CHIEF JUSTICE, JUSTICE THOMAS, and
JUSTICE ALITO, concluded:
1. The phrase “the waters of the United States” includes only those
relatively permanent, standing or continuously flowing bodies of wa
ter “forming geographic features” that are described in ordinary par
lance as “streams,” “oceans, rivers, [and] lakes,” Webster’s New In
ternational Dictionary 2882 (2d ed.), and does not include channels
through which water flows intermittently or ephemerally, or chan
nels that periodically provide drainage for rainfall. The Corps’ ex
pansive interpretation of that phrase is thus not “based on a permis
sible construction of the statute.” Chevron U. S. A. Inc. v. Natural
Resources Defense Council, Inc., 467 U. S. 837, 843. Pp. 12–21.
(a) While the meaning of “navigable waters” in the CWA is
broader than the traditional definition found in The Daniel Ball, 10
Wall. 557, see Solid Waste Agency of Northern Cook Cty. v. Army
Corps of Engineers, 531 U. S. 159, 167 (SWANCC); United States v.
Riverside Bayview Homes, Inc., 474 U. S. 121, 133, the CWA author
izes federal jurisdiction only over “waters.” The use of the definite
article “the” and the plural number “waters” show plainly that
§1362(7) does not refer to water in general, but more narrowly to wa
ter “[a]s found in streams,” “oceans, rivers, [and] lakes,” Webster’s
New International Dictionary 2882 (2d ed.). Those terms all connote
relatively permanent bodies of water, as opposed to ordinarily dry
channels through which water occasionally or intermittently flows.
Pp. 12–15.
(b) The Act’s use of the traditional phrase “navigable waters” fur
ther confirms that the CWA confers jurisdiction only over relatively
permanent bodies of water. Traditionally, such “waters” included
only discrete bodies of water, and the term still carries some of its
original substance, SWANCC, supra, at 172. This Court’s subsequent
interpretation of “the waters of the United States” in the CWA like
wise confirms this limitation. See, e.g., Riverside Bayview, supra, at
131. And the CWA itself categorizes the channels and conduits that
typically carry intermittent flows of water separately from “navigable
waters,” including them in the definition of “ ‘point sources,’ ” 33
U. S. C. §1362(14). Moreover, only the foregoing definition of “wa
ters” is consistent with CWA’s stated policy “to recognize, preserve,
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and protect the primary responsibilities and rights of the States . . .
to plan the development and use . . . of land and water resources
. . . .” §1251(b). In addition, “the waters of the United States” hardly
qualifies as the clear and manifest statement from Congress needed
to authorize intrusion into such an area of traditional state authority
as land-use regulation; and to authorize federal action that stretches
the limits of Congress’s commerce power. See SWANCC, supra, at
173. Pp. 15–21.
2. A wetland may not be considered “adjacent to” remote “waters of
the United States” based on a mere hydrologic connection. Riverside
Bayview rested on an inherent ambiguity in defining where the “wa
ter” ends and its abutting (“adjacent”) wetlands begin, permitting the
Corps to rely on ecological considerations only to resolve that ambigu
ity in favor of treating all abutting wetlands as waters. Isolated
ponds are not “waters of the United States” in their own right, see
SWANCC, supra, at 167, 171, and present no boundary-drawing
problem justifying the invocation of such ecological factors. Thus,
only those wetlands with a continuous surface connection to bodies
that are “waters of the United States” in their own right, so that
there is no clear demarcation between the two, are “adjacent” to such
waters and covered by the Act. Establishing coverage of the Rapanos
and Carabell sites requires finding that the adjacent channel con
tains a relatively permanent “wate[r] of the United States,” and that
each wetland has a continuous surface connection to that water,
making it difficult to determine where the water ends and the wet
land begins. Pp. 21–24.
3. Because the Sixth Circuit applied an incorrect standard to de
termine whether the wetlands at issue are covered “waters,” and be
cause of the paucity of the record, the cases are remanded for further
proceedings. P. 39.
JUSTICE KENNEDY concluded that the Sixth Circuit correctly recog
nized that a water or wetland constitutes “navigable waters” under
the Act if it possesses a “significant nexus” to waters that are naviga
ble in fact or that could reasonably be so made, Solid Waste Agency of
Northern Cook Cty. v. Army Corps of Engineers, 531 U. S. 159, 167,
172 (SWANCC), but did not consider all the factors necessary to de
termine that the lands in question had, or did not have, the requisite
nexus. United States v. Riverside Bayview Homes, Inc., 474 U. S.
121, and SWANCC establish the framework for the inquiry here.
The nexus required must be assessed in terms of the Act’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 dump
ing and filling in “waters of the United States,” §§1311(a), 1362(12).
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The rationale for the Act’s wetlands regulation, as the Corps has rec
ognized, is that wetlands can perform critical functions related to the
integrity of other waters—such as pollutant trapping, flood control,
and runoff storage. 33 C. F. R. §320.4(b)(2). Accordingly, wetlands
possess the requisite nexus, and thus come within the statutory
phrase “navigable waters,” if the wetlands, alone or in combination
with similarly situated lands in the region, significantly affect the
chemical, physical, and biological integrity of other covered waters
understood as navigable in the traditional sense. When, in contrast,
their effects on water quality are speculative or insubstantial, they
fall outside the zone fairly encompassed by the term “navigable wa
ters.” Because the Corps’ theory of jurisdiction in these cases—
adjacency to tributaries, however remote and insubstantial—goes be
yond the Riverside Bayview holding, its assertion of jurisdiction can
not rest on that case. The breadth of the Corps’ existing standard for
tributaries—which seems to leave room for regulating drains,
ditches, and streams remote from any navigable-in-fact water and
carrying only minor water-volumes toward it—precludes that stan
dard’s adoption as the determinative measure of whether adjacent
wetlands are likely to play an important role in the integrity of an
aquatic system comprising navigable waters as traditionally under
stood. Absent more specific regulations, the Corps must establish a
significant nexus on a case-by-case basis when seeking to regulate
wetlands based on adjacency to nonnavigable tributaries, in order to
avoid unreasonable applications of the Act. In the instant cases the
record contains evidence pointing to a possible significant nexus, but
neither the agency nor the reviewing courts considered the issue in
these terms. Thus, the cases should be remanded for further pro
ceedings. Pp. 1–30.

SCALIA, J., announced the judgment of the Court, and delivered an
opinion, in which ROBERTS, C. J., and THOMAS and ALITO, JJ., joined.
ROBERTS, C. J., filed a concurring opinion. KENNEDY, J., filed an opinion
concurring in the judgment. STEVENS, J., filed a dissenting opinion, in
which SOUTER, GINSBURG, and BREYER, JJ., joined. BREYER, J., filed a
dissenting opinion.
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Opinion of SCALIA, J.

NOTICE: This opinion is subject to formal revision before publication in the
preliminary print of the United States Reports. Readers are requested to
notify the Reporter of Decisions, Supreme Court of the United States, Wash
ington, D. C. 20543, of any typographical or other formal errors, in order
that corrections may be made before the preliminary print goes to press.

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 04–1034 and 04–1384
_________________

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS
04–1034 v.
UNITED STATES

JUNE CARABELL ET AL., PETITIONERS
04–1384 v.
UNITED STATES ARMY CORPS OF ENGINEERS ET AL.
ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE SIXTH CIRCUIT
[June 19, 2006]

JUSTICE SCALIA announced the judgment of the Court,
and delivered an opinion, in which THE CHIEF JUSTICE,
JUSTICE THOMAS, and JUSTICE ALITO join.
In April 1989, petitioner John A. Rapanos backfilled
wetlands on a parcel of land in Michigan that he owned
and sought to develop. This parcel included 54 acres of
land with sometimes-saturated soil conditions. The near
est body of navigable water was 11 to 20 miles away. 339
F. 3d 447, 449 (CA6 2003) (Rapanos I). Regulators had
informed Mr. Rapanos that his saturated fields were “wa
ters of the United States,” 33 U. S. C. §1362(7), that could
not be filled without a permit. Twelve years of criminal
and civil litigation ensued.
The burden of federal regulation on those who would
deposit fill material in locations denominated “waters of
the United States” is not trivial. In deciding whether to
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grant or deny a permit, the U. S. Army Corps of Engineers
(Corps) exercises the discretion of an enlightened despot,
relying on such factors as “economics,” “aesthetics,” “rec
reation,” and “in general, the needs and welfare of the
people,” 33 CFR §320.4(a) (2004).1 The average applicant
for an individual permit spends 788 days and $271,596 in
completing the process, and the average applicant for a
nationwide permit spends 313 days and $28,915—not
counting costs of mitigation or design changes. Sunding &
Zilberman, The Economics of Environmental Regulation
by Licensing: An Assessment of Recent Changes to the
Wetland Permitting Process, 42 Natural Resources J. 59,
74–76 (2002). “[O]ver $1.7 billion is spent each year by
the private and public sectors obtaining wetlands per
mits.” Id., at 81. These costs cannot be avoided, because
the Clean Water Act “impose[s] criminal liability,” as well
as steep civil fines, “on a broad range of ordinary indus
trial and commercial activities.” Hanousek v. United
States, 528 U. S. 1102, 1103 (2000) (THOMAS, J., dissent
ing from denial of certiorari). In this litigation, for exam
ple, for backfilling his own wet fields, Mr. Rapanos faced
63 months in prison and hundreds of thousands of dollars
in criminal and civil fines. See United States v. Rapanos,
235 F. 3d 256, 260 (CA6 2000).
The enforcement proceedings against Mr. Rapanos are a
small part of the immense expansion of federal regulation
of land use that has occurred under the Clean Water Act—

——————
1 In issuing permits, the Corps directs that “[a]ll factors which may be

relevant to the proposal must be considered including the cumulative
effects thereof: among those are conservation, economics, aesthetics,
general environmental concerns, wetlands, historic properties, fish and
wildlife values, flood hazards, floodplain values, land use, navigation,
shore erosion and accretion, recreation, water supply and conservation,
water quality, energy needs, safety, food and fiber production, mineral
needs, considerations of property ownership and, in general, the needs
and welfare of the people.” §320.4(a).
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Opinion of SCALIA, J.

without any change in the governing statute—during the
past five Presidential administrations. In the last three
decades, the Corps and the Environmental Protection Agency
(EPA) have interpreted their jurisdiction over “the waters of
the United States” to cover 270-to-300 million acres of
swampy lands in the United States—including half of
Alaska and an area the size of California in the lower 48
States. And that was just the beginning. The Corps has
also asserted jurisdiction over virtually any parcel of land
containing a channel or conduit—whether man-made or
natural, broad or narrow, permanent or ephemeral—
through which rainwater or drainage may occasionally or
intermittently flow. On this view, the federally regulated
“waters of the United States” include storm drains, road
side ditches, ripples of sand in the desert that may contain
water once a year, and lands that are covered by floodwa
ters once every 100 years. Because they include the land
containing storm sewers and desert washes, the statutory
“waters of the United States” engulf entire cities and
immense arid wastelands. In fact, the entire land area of
the United States lies in some drainage basin, and an
endless network of visible channels furrows the entire
surface, containing water ephemerally wherever the rain
falls. Any plot of land containing such a channel may
potentially be regulated as a “water of the United States.”
I
Congress passed the Clean Water Act (CWA or Act) in
1972. The Act’s stated objective is “to restore and main
tain the chemical, physical, and biological integrity of the
Nation’s waters.” 86 Stat. 816, 33 U. S. C. §1251(a). The
Act also states that “[i]t is the policy of Congress to recog
nize, preserve, and protect the primary responsibilities
and rights of States to prevent, reduce, and eliminate
pollution, to plan the development and use (including
restoration, preservation, and enhancement) of land and
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water resources, and to consult with the Administrator in
the exercise of his authority under this chapter.” §1251(b).
One of the statute’s principal provisions is 33 U. S. C.
§1311(a), which provides that “the discharge of any pollut
ant by any person shall be unlawful.” “The discharge of a
pollutant” is defined broadly to include “any addition of
any pollutant to navigable waters from any point source,”
§1362(12), and “pollutant” is defined broadly to include not
only traditional contaminants but also solids such as
“dredged spoil, . . . rock, sand, [and] cellar dirt,” §1362(6).
And, most relevant here, the CWA defines “navigable
waters” as “the waters of the United States, including the
territorial seas.” §1362(7).
The Act also provides certain exceptions to its prohibi
tion of “the discharge of any pollutant by any person.”
§1311(a). Section 1342(a) authorizes the Administrator of
the EPA to “issue a permit for the discharge of any pollut
ant, . . . notwithstanding section 1311(a) of this title.”
Section 1344 authorizes the Secretary of the Army, acting
through the Corps, to “issue permits . . . for the discharge
of dredged or fill material into the navigable waters at
specified disposal sites.” §1344(a), (d). It is the discharge
of “dredged or fill material”—which, unlike traditional
water pollutants, are solids that do not readily wash
downstream—that we consider today.
For a century prior to the CWA, we had interpreted the
phrase “navigable waters of the United States” in the Act’s
predecessor statutes to refer to interstate waters that are
“navigable in fact” or readily susceptible of being rendered
so. The Daniel Ball, 10 Wall. 557, 563 (1871); see also
United States v. Appalachian Elec. Power Co., 311 U. S.
377, 406 (1940). After passage of the CWA, the Corps
initially adopted this traditional judicial definition for the
Act’s term “navigable waters.” See 39 Fed. Reg. 12119,
codified at 33 CFR §209.120(d)(1) (1974); see also Solid
Waste Agency of Northern Cook Cty. v. Army Corps of
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Engineers, 531 U. S. 159, 168 (2001) (SWANCC). After a
District Court enjoined these regulations as too narrow,
Natural Resources Defense Council, Inc. v. Callaway, 392
F. Supp. 685, 686 (DC 1975), the Corps adopted a far
broader definition. See 40 Fed. Reg. 31324–31325 (1975);
42 Fed. Reg. 37144 (1977). The Corps’ new regulations
deliberately sought to extend the definition of “the waters
of the United States” to the outer limits of Congress’s
commerce power. See id., at 37144, n. 2.
The Corps’ current regulations interpret “the waters of
the United States” to include, in addition to traditional
interstate navigable waters, 33 CFR §328.3(a)(1) (2004),
“[a]ll interstate waters including interstate wetlands,”
§328.3(a)(2); “[a]ll other waters such as intrastate lakes,
rivers, streams (including intermittent streams), mudflats,
sandflats, wetlands, sloughs, prairie potholes, wet mead
ows, playa lakes, or natural ponds, the use, degradation or
destruction of which could affect interstate or foreign
commerce,” §328.3(a)(3); “[t]ributaries of [such] waters,”
§328.3(a)(5); and “[w]etlands adjacent to [such] waters
[and tributaries] (other than waters that are themselves
wetlands),” §328.3(a)(7). The regulation defines “adjacent”
wetlands as those “bordering, contiguous [to], or neighbor
ing” waters of the United States. §328.3(c). It specifically
provides that “[w]etlands separated from other waters of
the United States by man-made dikes or barriers, natural
river berms, beach dunes and the like are ‘adjacent wet
lands.’ ” Ibid.
We first addressed the proper interpretation of 33
U. S. C. §1362(7)’s phrase “the waters of the United
States” in United States v. Riverside Bayview Homes, Inc.,
474 U. S. 121 (1985). That case concerned a wetland that
“was adjacent to a body of navigable water,” because “the
area characterized by saturated soil conditions and wet
land vegetation extended beyond the boundary of respon
dent’s property to . . . a navigable waterway.” Id., at 131;
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see also 33 CFR §328.3(b) (2004). Noting that “the transi
tion from water to solid ground is not necessarily or even
typically an abrupt one,” and that “the Corps must neces
sarily choose some point at which water ends and land
begins,” 474 U. S., at 132, we upheld the Corps’ interpre
tation of “the waters of the United States” to include
wetlands that “actually abut[ted] on” traditional navigable
waters. Id., at 135.
Following our decision in Riverside Bayview, the Corps
adopted increasingly broad interpretations of its own
regulations under the Act. For example, in 1986, to “clar
ify” the reach of its jurisdiction, the Corps announced the
so-called “Migratory Bird Rule,” which purported to extend
its jurisdiction to any intrastate waters “[w]hich are or
would be used as habitat” by migratory birds. 51 Fed. Reg.
41217; see also SWANCC, supra, at 163–164. In addition,
the Corps interpreted its own regulations to include
“ephemeral streams” and “drainage ditches” as “tributar
ies” that are part of the “waters of the United States,” see
33 CFR §328.3(a)(5), provided that they have a perceptible
“ordinary high water mark” as defined in §328.3(e). 65
Fed. Reg. 12823 (2000). This interpretation extended “the
waters of the United States” to virtually any land feature
over which rainwater or drainage passes and leaves a visi
ble mark—even if only “the presence of litter and debris.”
33 CFR §328.3(e). See also U. S. General Accounting
Office, Report to the Chairman, Subcommittee on Energy
Policy, Natural Resources and Regulating Affairs, Commit
tee on Government Reform, House of Representatives,
Waters and Wetlands: Corps of Engineers Needs to Evalu
ate Its District Office Practices in Determining Juris
diction, GAO–04–297, pp. 20–22 (Feb. 2004) (hereinafter
GAO Report), http://www.gao.gov/new.items/d04297.pdf
(all Internet materials as visited June 9, 2006, and avail
able in Clerk of Court’s case file). Prior to our decision in
SWANCC, lower courts upheld the application of this
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expansive definition of “tributaries” to such entities as
storm sewers that contained flow to covered waters during
heavy rainfall, United States v. Eidson, 108 F. 3d 1336,
1340–1342 (CA11 1997), and dry arroyos connected to
remote waters through the flow of groundwater over “cen
turies,” Quivira Mining Co. v. EPA, 765 F. 2d 126, 129
(CA10 1985).
In SWANCC, we considered the application of the Corps’
“Migratory Bird Rule” to “an abandoned sand and gravel
pit in northern Illinois.” 531 U. S., at 162. Observing that
“[i]t was the significant nexus between the wetlands and
‘navigable waters’ that informed our reading of the CWA
in Riverside Bayview,” id., at 167 (emphasis added), we
held that Riverside Bayview did not establish “that the
jurisdiction of the Corps extends to ponds that are not
adjacent to open water.” 531 U. S., at 168 (emphasis
deleted). On the contrary, we held that “nonnavigable,
isolated, intrastate waters,” id., at 171—which, unlike the
wetlands at issue in Riverside Bayview, did not “actually
abu[t] on a navigable waterway,” 531 U. S., at 167—were
not included as “waters of the United States.”
Following our decision in SWANCC, the Corps did not
significantly revise its theory of federal jurisdiction under
§1344(a). The Corps provided notice of a proposed rule-
making in light of SWANCC, 68 Fed. Reg. 1991 (2003), but
ultimately did not amend its published regulations. Be
cause SWANCC did not directly address tributaries, the
Corps notified its field staff that they “should continue to
assert jurisdiction over traditional navigable waters . . .
and, generally speaking, their tributary systems (and
adjacent wetlands).” 68 Fed. Reg. 1998. In addition,
because SWANCC did not overrule Riverside Bayview, the
Corps continues to assert jurisdiction over waters
“ ‘neighboring’ ” traditional navigable waters and their
tributaries. 68 Fed. Reg. 1997 (quoting 33 CFR §328.3(c)
(2003)).
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Even after SWANCC, the lower courts have continued to
uphold the Corps’ sweeping assertions of jurisdiction over
ephemeral channels and drains as “tributaries.” For
example, courts have held that jurisdictional “tributaries”
include the “intermittent flow of surface water through
approximately 2.4 miles of natural streams and manmade
ditches (paralleling and crossing under I–64),” Treacy v.
Newdunn Assoc., 344 F. 3d 407, 410 (CA4 2003); a “road
side ditch” whose water took “a winding, thirty-two-mile
path to the Chesapeake Bay,” United States v. Deaton, 332
F. 3d 698, 702 (CA4 2003); irrigation ditches and drains
that intermittently connect to covered waters, Community
Assn. for Restoration of Environment v. Henry Bosma
Dairy, 305 F. 3d 943, 954–955 (CA9 2002); Headwaters,
Inc. v. Talent Irrigation Dist., 243 F. 3d 526, 534 (CA9
2001); and (most implausibly of all) the “washes and ar
royos” of an “arid development site,” located in the middle
of the desert, through which “water courses . . . during
periods of heavy rain,” Save Our Sonoran, Inc. v. Flowers,
408 F. 3d 1113, 1118 (CA9 2005).2
These judicial constructions of “tributaries” are not
outliers. Rather, they reflect the breadth of the Corps’
determinations in the field. The Corps’ enforcement prac
tices vary somewhat from district to district because “the
definitions used to make jurisdictional determinations”
are deliberately left “vague.” GAO Report 26; see also id.,
at 22. But district offices of the Corps have treated, as

——————
2 We are indebted to the Sonoran court for a famous exchange, from

the movie Casablanca (Warner Bros. 1942), which portrays most vividly
the absurdity of finding the desert filled with waters:
“ ‘Captain Renault [Claude Rains]: “What in heaven’s name brought
you to Casablanca?”
“ ‘Rick [Humphrey Bogart]: “My health. I came to Casablanca for the
waters.”
“ ‘Captain Renault: “The waters? What waters? We’re in the desert.”
“ ‘Rick: “I was misinformed.’ ” 408 F. 3d, at 1117.
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“waters of the United States,” such typically dry land
features as “arroyos, coulees, and washes,” as well as other
“channels that might have little water flow in a given
year.” Id., at 20–21. They have also applied that defini
tion to such manmade, intermittently flowing features as
“drain tiles, storm drains systems, and culverts.” Id., at
24 (footnote omitted).
In addition to “tributaries,” the Corps and the lower
courts have also continued to define “adjacent” wetlands
broadly after SWANCC. For example, some of the Corps’
district offices have concluded that wetlands are “adja
cent” to covered waters if they are hydrologically con
nected “through directional sheet flow during storm
events,” GAO Report 18, or if they lie within the “100-year
floodplain” of a body of water—that is, they are connected
to the navigable water by flooding, on average, once every
100 years, id., at 17, and n. 16. Others have concluded
that presence within 200 feet of a tributary automatically
renders a wetland “adjacent” and jurisdictional. Id., at 19.
And the Corps has successfully defended such theories of
“adjacency” in the courts, even after SWANCC’s excision of
“isolated” waters and wetlands from the Act’s coverage.
One court has held since SWANCC that wetlands sepa
rated from flood control channels by 70-foot-wide berms,
atop which ran maintenance roads, had a “significant
nexus” to covered waters because, inter alia, they lay
“within the 100 year floodplain of tidal waters.” Baccarat
Fremont Developers, LLC v. Army Corps of Engineers, 425
F. 3d 1150, 1152, 1157 (CA9 2005). In one of the cases
before us today, the Sixth Circuit held, in agreement with
“[t]he majority of courts,” that “while a hydrological con
nection between the non-navigable and navigable waters
is required, there is no ‘direct abutment’ requirement”
under SWANCC for “ ‘adjacency.’ ” 376 F. 3d 629, 639
(2004) (Rapanos II). And even the most insubstantial
hydrologic connection may be held to constitute a “signifi
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Opinion of SCALIA, J.

cant nexus.” One court distinguished SWANCC on the
ground that “a molecule of water residing in one of these
pits or ponds [in SWANCC] could not mix with molecules
from other bodies of water”—whereas, in the case before
it, “water molecules currently present in the wetlands will
inevitably flow towards and mix with water from connect
ing bodies,” and “[a] drop of rainwater landing in the Site
is certain to intermingle with water from the [nearby
river].” United States v. Rueth Development Co., 189
F. Supp. 2d 874, 877–878 (ND Ind. 2002).
II
In these consolidated cases, we consider whether four
Michigan wetlands, which lie near ditches or man-made
drains that eventually empty into traditional navigable
waters, constitute “waters of the United States” within the
meaning of the Act. Petitioners in No. 04–1034, the Ra
panos and their affiliated businesses, deposited fill mate
rial without a permit into wetlands on three sites near
Midland, Michigan: the “Salzburg site,” the “Hines Road
site,” and the “Pine River site.” The wetlands at the Salz
burg site are connected to a man-made drain, which
drains into Hoppler Creek, which flows into the
Kawkawlin River, which empties into Saginaw Bay and
Lake Huron. See Brief for United States in No. 04–1034,
p. 11; 339 F. 3d, at 449. The wetlands at the Hines Road
site are connected to something called the “Rose Drain,”
which has a surface connection to the Tittabawassee
River. App. to Pet. for Cert. in No. 04–1034, pp. A23, B20.
And the wetlands at the Pine River site have a surface
connection to the Pine River, which flows into Lake
Huron. Id., at A23–A24, B26. It is not clear whether the
connections between these wetlands and the nearby drains
and ditches are continuous or intermittent, or whether the
nearby drains and ditches contain continuous or merely
occasional flows of water.
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The United States brought civil enforcement proceed
ings against the Rapanos petitioners. The District Court
found that the three described wetlands were “within
federal jurisdiction” because they were “adjacent to other
waters of the United States,” and held petitioners liable
for violations of the CWA at those sites. Id., at B32–B35.
On appeal, the United States Court of Appeals for the
Sixth Circuit affirmed, holding that there was federal
jurisdiction over the wetlands at all three sites because
“there were hydrological connections between all three
sites and corresponding adjacent tributaries of navigable
waters.” 376 F. 3d, at 643.
Petitioners in No. 04–1384, the Carabells, were denied a
permit to deposit fill material in a wetland located on a
triangular parcel of land about one mile from Lake St.
Clair. A man-made drainage ditch runs along one side of
the wetland, separated from it by a 4-foot-wide man-made
berm. The berm is largely or entirely impermeable to
water and blocks drainage from the wetland, though it
may permit occasional overflow to the ditch. The ditch
empties into another ditch or a drain, which connects to
Auvase Creek, which empties into Lake St. Clair. See
App. to Pet. for Cert. in No. 04–1384, pp. 2a–3a.
After exhausting administrative appeals, the Carabell
petitioners filed suit in the District Court, challenging the
exercise of federal regulatory jurisdiction over their site.
The District Court ruled that there was federal jurisdic
tion because the wetland “is adjacent to neighboring tribu
taries of navigable waters and has a significant nexus to
‘waters of the United States.’ ” Id., at 49a. Again the
Sixth Circuit affirmed, holding that the Carabell wetland
was “adjacent” to navigable waters. 391 F. 3d 704, 708
(2004) (Carabell).
We granted certiorari and consolidated the cases, 546
U. S. ___ (2005), to decide whether these wetlands consti
tute “waters of the United States” under the Act, and if so,
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Opinion of SCALIA, J.

whether the Act is constitutional.
III
The Rapanos petitioners contend that the terms “navi
gable waters” and “waters of the United States” in the Act
must be limited to the traditional definition of The Daniel
Ball, which required that the “waters” be navigable in
fact, or susceptible of being rendered so. See 10 Wall., at
563. But this definition cannot be applied wholesale to
the CWA. The Act uses the phrase “navigable waters” as
a defined term, and the definition is simply “the waters of
the United States.” 33 U. S. C. §1362(7). Moreover, the
Act provides, in certain circumstances, for the substitu
tion of state for federal jurisdiction over “navigable waters
. . . other than those waters which are presently used, or
are susceptible to use in their natural condition or by
reasonable improvement as a means to transport inter
state or foreign commerce . . . including wetlands adjacent
thereto.” §1344(g)(1) (emphasis added). This provision
shows that the Act’s term “navigable waters” includes
something more than traditional navigable waters. We
have twice stated that the meaning of “navigable waters”
in the Act is broader than the traditional understanding of
that term, SWANCC, 531 U. S., at 167; Riverside Bayview,
474 U. S., at 133.3 We have also emphasized, however,
——————
3 One possibility, which we ultimately find unsatisfactory, is that the

“other” waters covered by 33 U. S. C. §1344(g)(1) are strictly intrastate
waters that are traditionally navigable. But it would be unreasonable
to interpret “the waters of the United States” to include all and only
traditional navigable waters, both interstate and intrastate. This
would preserve the traditional import of the qualifier “navigable” in the
defined term “navigable waters,” at the cost of depriving the qualifier
“of the United States” in the definition of all meaning. As traditionally
understood, the latter qualifier excludes intrastate waters, whether
navigable or not. See The Daniel Ball, 10 Wall. 557, 563 (1871). In
SWANCC, we held that “navigable” retained something of its tradi
tional import. 531 U. S., at 172. A fortiori, the phrase “of the United
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Opinion of SCALIA, J.

that the qualifier “navigable” is not devoid of significance,
SWANCC, supra, at 172.
We need not decide the precise extent to which the
qualifiers “navigable” and “of the United States” restrict
the coverage of the Act. Whatever the scope of these
qualifiers, the CWA authorizes federal jurisdiction only
over “waters.” 33 U. S. C. §1362(7). The only natural
definition of the term “waters,” our prior and subsequent
judicial constructions of it, clear evidence from other pro
visions of the statute, and this Court’s canons of construc
tion all confirm that “the waters of the United States” in
§1362(7) cannot bear the expansive meaning that the
Corps would give it.
The Corps’ expansive approach might be arguable if the
CSA defined “navigable waters” as “water of the United
States.” But “the waters of the United States” is some
thing else. The use of the definite article (“the”) and the
plural number (“waters”) show plainly that §1362(7) does
not refer to water in general. In this form, “the waters”
refers more narrowly to water “[a]s found in streams and
bodies forming geographical features such as oceans,
rivers, [and] lakes,” or “the flowing or moving masses, as
of waves or floods, making up such streams or bodies.”
Webster’s New International Dictionary 2882 (2d ed.
1954) (hereinafter Webster’s Second).4 On this definition,
“the waters of the United States” include only relatively
——————
States” in the definition retains some of its traditional meaning.
4 JUSTICE KENNEDY observes, post, at 13 (opinion concurring in judg

ment), that the dictionary approves an alternative, somewhat poetic
usage of “waters” as connoting “[a] flood or inundation; as the waters
have fallen. ‘The peril of waters, wind, and rocks.’ Shak.” Webster’s
Second 2882. It seems to us wholly unreasonable to interpret the
statute as regulating only “floods” and “inundations” rather than
traditional waterways—and strange to suppose that Congress had
waxed Shakespearean in the definition section of an otherwise prosaic,
indeed downright tedious, statute. The duller and more commonplace
meaning is obviously intended.
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Opinion of SCALIA, J.

permanent, standing or flowing bodies of water.5 The
definition refers to water as found in “streams,” “oceans,”
“rivers,” “lakes,” and “bodies” of water “forming geographi
cal features.” Ibid. All of these terms connote continu
ously present, fixed bodies of water, as opposed to ordinar
ily dry channels through which water occasionally or
intermittently flows. Even the least substantial of the
definition’s terms, namely “streams,” connotes a continu
ous flow of water in a permanent channel—especially
when used in company with other terms such as “rivers,”
“lakes,” and “oceans.”6 None of these terms encompasses
——————
5 By describing “waters” as “relatively permanent,” we do not necessar

ily exclude streams, rivers, or lakes that might dry up in extraordinary
circumstances, such as drought. We also do not necessarily exclude
seasonal rivers, which contain continuous flow during some months of
the year but no flow during dry months—such as the 290-day, continu
ously flowing stream postulated by JUSTICE STEVENS’ dissent (hereinaf
ter the dissent), post, at 15. Common sense and common usage distin
guish between a wash and seasonal river.
Though scientifically precise distinctions between “perennial” and
“intermittent” flows are no doubt available, see, e.g., Dept. of Interior,
U. S. Geological Survey, E. Hedman & W. Osterkamp, Streamflow
Characteristics Related to Channel Geometry of Streams in Western
United States 15 (1982) (Water-Supply Paper 2193), we have no occa
sion in this litigation to decide exactly when the drying-up of a stream
bed is continuous and frequent enough to disqualify the channel as a
“wate[r] of the United States.” It suffices for present purposes that
channels containing permanent flow are plainly within the definition,
and that the dissent’s “intermittent” and “ephemeral” streams, post, at
16 (opinion of STEVENS, J.)—that is, streams whose flow is “[c]oming
and going at intervals . . . [b]roken, fitful,” Webster’s Second 1296, or
“existing only, or no longer than, a day; diurnal . . . short-lived,” id., at
857—are not.
6 The principal definition of “stream” likewise includes reference to

such permanent, geographically fixed bodies of water: “[a] current or
course of water or other fluid, flowing on the earth, as a river, brook,
etc.” Id., at 2493 (emphasis added). The other definitions of “stream”
repeatedly emphasize the requirement of continuous flow: “[a] steady
flow, as of water, air, gas, or the like”; “[a]nything issuing or moving
with continued succession of parts”; “[a] continued current or course;
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Opinion of SCALIA, J.

transitory puddles or ephemeral flows of water.
The restriction of “the waters of the United States” to
exclude channels containing merely intermittent or
ephemeral flow also accords with the commonsense under
standing of the term. In applying the definition to
“ephemeral streams,” “wet meadows,” storm sewers and
culverts, “directional sheet flow during storm events,”
drain tiles, man-made drainage ditches, and dry arroyos in
the middle of the desert, the Corps has stretched the term
“waters of the United States” beyond parody. The plain
language of the statute simply does not authorize this
“Land Is Waters” approach to federal jurisdiction.
In addition, the Act’s use of the traditional phrase “navi
gable waters” (the defined term) further confirms that it
confers jurisdiction only over relatively permanent bodies
of water. The Act adopted that traditional term from its
predecessor statutes. See SWANCC, 531 U. S., at 180
(STEVENS, J., dissenting). On the traditional understand
ing, “navigable waters” included only discrete bodies of
water. For example, in The Daniel Ball, we used the terms
“waters” and “rivers” interchangeably. 10 Wall., at 563.
And in Appalachian Electric, we consistently referred to
——————
current; drift.” Ibid. (emphases added). The definition of the verb form
of “stream” contains a similar emphasis on continuity: “[t]o issue or
flow in a stream; to issue freely or move in a continuous flow or course.”
Ibid. (emphasis added). On these definitions, therefore, the Corps’
phrases “intermittent streams,” 33 CFR §328.3(a)(3) (2004), and
“ephemeral streams,” 65 Fed. Reg. 12823 (2000), are—like Senator
Bentsen’s “ ‘flowing gullies,’ ” post, at 16, n. 11 (opinion of STEVENS, J.)—
useful oxymora. Properly speaking, such entities constitute extant
“streams” only while they are “continuous[ly] flow[ing]”; and the usu
ally dry channels that contain them are never “streams.” JUSTICE
KENNEDY apparently concedes that “an intermittent flow can constitute
a stream” only “while it is flowing,” post, at 13 (emphasis added)—
which would mean that the channel is a “water” covered by the Act only
during those times when water flow actually occurs. But no one con
tends that federal jurisdiction appears and evaporates along with the
water in such regularly dry channels.
16 RAPANOS v. UNITED STATES

Opinion of SCALIA, J.

the “navigable waters” as “waterways.” 311 U. S., at 407–
409. Plainly, because such “waters” had to be navigable in
fact or susceptible of being rendered so, the term did not
include ephemeral flows. As we noted in SWANCC, the
traditional term “navigable waters”—even though defined
as “the waters of the United States”—carries some of its
original substance: “[I]t is one thing to give a word limited
effect and quite another to give it no effect whatever.” 531
U. S., at 172. That limited effect includes, at bare mini
mum, the ordinary presence of water.
Our subsequent interpretation of the phrase “the waters
of the United States” in the CWA likewise confirms this
limitation of its scope. In Riverside Bayview, we stated
that the phrase in the Act referred primarily to “rivers,
streams, and other hydrographic features more conven
tionally identifiable as ‘waters’ ” than the wetlands adja
cent to such features. 474 U. S., at 131 (emphasis added).
We thus echoed the dictionary definition of “waters” as
referring to “streams and bodies forming geographical
features such as oceans, rivers, [and] lakes.” Webster’s
Second 2882 (emphasis added). Though we upheld in that
case the inclusion of wetlands abutting such a “hydro
graphic featur[e]”—principally due to the difficulty of
drawing any clear boundary between the two, see 474
U. S., at 132; Part IV, infra—nowhere did we suggest that
“the waters of the United States” should be expanded to
include, in their own right, entities other than “hydro
graphic features more conventionally identifiable as ‘wa
ters.’ ” Likewise, in both Riverside Bayview and SWANCC,
we repeatedly described the “navigable waters” covered by
the Act as “open water” and “open waters.” See Riverside
Bayview, supra, at 132, and n. 8, 134; SWANCC, supra, at
167, 172. Under no rational interpretation are typically
dry channels described as “open waters.”
Most significant of all, the CWA itself categorizes the
channels and conduits that typically carry intermittent
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Opinion of SCALIA, J.

flows of water separately from “navigable waters,” by
including them in the definition of “ ‘point source.’ ” The
Act defines “ ‘point source’ ” as “any discernible, confined
and discrete conveyance, including but not limited to any
pipe, ditch, channel, tunnel, conduit, well, discrete fissure,
container, rolling stock, concentrated animal feeding
operation, or vessel or other floating craft, from which
pollutants are or may be discharged.” 33 U. S. C.
§1362(14). It also defines “ ‘discharge of a pollutant’ ” as
“any addition of any pollutant to navigable waters from
any point source.” §1362(12)(A) (emphases added). The
definitions thus conceive of “point sources” and “navigable
waters” as separate and distinct categories. The definition
of “discharge” would make little sense if the two categories
were significantly overlapping. The separate classification
of “ditch[es], channel[s], and conduit[s]”—which are terms
ordinarily used to describe the watercourses through
which intermittent waters typically flow—shows that these
are, by and large, not “waters of the United States.”7
——————
7 It is of course true, as the dissent and JUSTICE KENNEDY both ob

serve, that ditches, channels, conduits and the like “can all hold water
permanently as well as intermittently,” post, at 17 (opinion of STEVENS,
J.); see also post, at 14–15 (opinion of KENNEDY, J.). But when they do,
we usually refer to them as “rivers,” “creeks,” or “streams.” A perma
nently flooded ditch around a castle is technically a “ditch,” but (be
cause it is permanently filled with water) we normally describe it as a
“moat.” See Webster’s Second 1575. And a permanently flooded man-
made ditch used for navigation is normally described, not as a “ditch,”
but as a “canal.” See id., at 388. Likewise, an open channel through
which water permanently flows is ordinarily described as a “stream,”
not as a “channel,” because of the continuous presence of water. This
distinction is particularly apt in the context of a statute regulating
water quality, rather than (for example) the shape of stream beds. Cf.
Jennison v. Kirk, 98 U. S. 453, 454–456 (1879) (referring to man-made
channels as “ditches” when the alleged injury arose from physical
damage to the banks of the ditch); PUD No. 1 of Jefferson Cty. v.
Washington Dept. of Ecology, 511 U. S. 700, 709 (1994) (referring to a
water-filled tube as a “tunnel” in order to describe the shape of the
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Opinion of SCALIA, J.

Moreover, only the foregoing definition of “waters” is
consistent with the CWA’s stated “policy of Congress to
recognize, preserve, and protect the primary responsibili
ties and rights of the States to prevent, reduce, and elimi
nate pollution, [and] to plan the development and use
(including restoration, preservation, and enhancement) of
land and water resources . . . .” §1251(b). This statement
of policy was included in the Act as enacted in 1972, see 86
Stat. 816, prior to the addition of the optional state ad
ministration program in the 1977 amendments, see 91
Stat. 1601. Thus the policy plainly referred to something
beyond the subsequently added state administration
program of 33 U. S. C. §1344(g)–(l). But the expansive
theory advanced by the Corps, rather than “preserv[ing]
the primary rights and responsibilities of the States,”
would have brought virtually all “plan[ning of] the devel
opment and use . . . of land and water resources” by the
States under federal control. It is therefore an unlikely

——————

conveyance, not the fact that it was water-filled), both cited post, at 17,

n. 12 (opinion of STEVENS, J.). On its only natural reading, such a
statute that treats “waters” separately from “ditch[es], channel[s],
tunnel[s], and conduit[s],” thereby distinguishes between continuously
flowing “waters” and channels containing only an occasional or inter
mittent flow.
It is also true that highly artificial, manufactured, enclosed convey
ance systems—such as “sewage treatment plants,” post, at 15 (opinion
of KENNEDY, J.), and the “mains, pipes, hydrants, machinery, buildings,
and other appurtenances and incidents” of the city of Knoxville’s
“system of waterworks,” Knoxville Water Co. v. Knoxville, 200 U. S. 22,
27 (1906), cited post, at 17, n. 12 (opinion of STEVENS, J.)—likely do not
qualify as “waters of the United States,” despite the fact that they may
contain continuous flows of water. See post, at 15 (opinion of KENNEDY,
J.); post, at 17, n. 12 (opinion of STEVENS, J.). But this does not contra
dict our interpretation, which asserts that relatively continuous flow is
a necessary condition for qualification as a “water,” not an adequate
condition. Just as ordinary usage does not treat typically dry beds as
“waters,” so also it does not treat such elaborate, man-made, enclosed
systems as “waters” on a par with “streams,” “rivers,” and “oceans.”
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Opinion of SCALIA, J.

reading of the phrase “the waters of the United States.”8
Even if the phrase “the waters of the United States”
were ambiguous as applied to intermittent flows, our own
canons of construction would establish that the Corps’
interpretation of the statute is impermissible. As we
noted in SWANCC, the Government’s expansive interpre
tation would “result in a significant impingement of the
States’ traditional and primary power over land and water
use.” 531 U. S., at 174. Regulation of land use, as through
the issuance of the development permits sought by peti
tioners in both of these cases, is a quintessential state and
local power. See FERC v. Mississippi, 456 U. S. 742, 768,
n. 30 (1982); Hess v. Port Authority Trans-Hudson Corpo
ration, 513 U. S. 30, 44 (1994). The extensive federal
jurisdiction urged by the Government would authorize the
Corps to function as a de facto regulator of immense
stretches of intrastate land—an authority the agency has
shown its willingness to exercise with the scope of discre
tion that would befit a local zoning board. See 33 CFR
§320.4(a)(1) (2004). We ordinarily expect a “clear and
manifest” statement from Congress to authorize an un
precedented intrusion into traditional state authority. See
BFP v. Resolution Trust Corporation, 511 U. S. 531, 544
(1994). The phrase “the waters of the United States”
hardly qualifies.
Likewise, just as we noted in SWANCC, the Corps’
——————
8 JUSTICE KENNEDY contends that the Corps’ preservation of the “re
sponsibilities and rights” of the States is adequately demonstrated by
the fact that “33 States and the District of Columbia have filed an amici
brief in this litigation” in favor of the Corps’ interpretation, post, at 20.
But it makes no difference to the statute’s stated purpose of preserving
States’ “rights and responsibilities,” §1251(b), that some States wish to
unburden themselves of them. Legislative and executive officers of the
States may be content to leave “responsibilit[y]” with the Corps because
it is attractive to shift to another entity controversial decisions disputed
between politically powerful, rival interests. That, however, is not
what the statute provides.
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Opinion of SCALIA, J.

interpretation stretches the outer limits of Congress’s
commerce power and raises difficult questions about the
ultimate scope of that power. See 531 U. S., at 173. (In
developing the current regulations, the Corps consciously
sought to extend its authority to the farthest reaches of
the commerce power. See 42 Fed. Reg. 37127 (1977).)
Even if the term “the waters of the United States” were
ambiguous as applied to channels that sometimes host
ephemeral flows of water (which it is not), we would ex
pect a clearer statement from Congress to authorize an
agency theory of jurisdiction that presses the envelope of
constitutional validity. See Edward J. DeBartolo Corp. v.
Florida Gulf Coast Building & Constr. Trades Council,
485 U. S. 568, 575 (1988).9
In sum, on its only plausible interpretation, the phrase
“the waters of the United States” includes only those
relatively permanent, standing or continuously flowing
bodies of water “forming geographic features” that are
described in ordinary parlance as “streams[,] . . . oceans,
rivers, [and] lakes.” See Webster’s Second 2882. The
phrase does not include channels through which water
——————
9 JUSTICE KENNEDY objects that our reliance on these two clear-

statement rules is inappropriate because “the plurality’s interpretation
does not fit the avoidance concerns that it raises,” post, at 19—that is,
because our resolution both eliminates some jurisdiction that is clearly
constitutional and traditionally federal, and retains some that is
questionably constitutional and traditionally local. But a clear-
statement rule can carry one only so far as the statutory text permits.
Our resolution, unlike JUSTICE KENNEDY’s, keeps both the overinclusion
and the underinclusion to the minimum consistent with the statutory
text. JUSTICE KENNEDY’s reading—despite disregarding the text—fares
no better than ours as a precise “fit” for the “avoidance concerns” that
he also acknowledges. He admits, post, at 25, that “the significant
nexus requirement may not align perfectly with the traditional extent
of federal authority” over navigable waters—an admission that “tests
the limits of understatement,” Gonzales v. Oregon, 126 S. Ct. 904, 932
(2005) (SCALIA, J., dissenting)—and it aligns even worse with the
preservation of traditional state land-use regulation.
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Opinion of SCALIA, J.

flows intermittently or ephemerally, or channels that
periodically provide drainage for rainfall. The Corps’
expansive interpretation of the “the waters of the United
States” is thus not “based on a permissible construction of
the statute.” Chevron U. S. A. Inc. v. Natural Resources
Defense Council, Inc., 467 U. S. 837, 843 (1984).
IV
In Carabell, the Sixth Circuit held that the nearby ditch
constituted a “tributary” and thus a “water of the United
States” under 33 CFR §328.3(a)(5) (2004). See 391 F. 3d, at
708–709. Likewise in Rapanos, the Sixth Circuit held that
the nearby ditches were “tributaries” under §328(a)(5). 376
F. 3d, at 643. But Rapanos II also stated that, even if the
ditches were not “waters of the United States,” the wet
lands were “adjacent” to remote traditional navigable
waters in virtue of the wetlands’ “hydrological connection”
to them. See id., at 639–640. This statement reflects the
practice of the Corps’ district offices, which may “assert
jurisdiction over a wetland without regulating the ditch
connecting it to a water of the United States.” GAO Re
port 23. We therefore address in this Part whether a
wetland may be considered “adjacent to” remote “waters of
the United States,” because of a mere hydrologic connec
tion to them.
In Riverside Bayview, we noted the textual difficulty in
including “wetlands” as a subset of “waters”: “On a purely
linguistic level, it may appear unreasonable to classify
‘lands,’ wet or otherwise, as ‘waters.’ ” 474 U. S., at 132.
We acknowledged, however, that there was an inherent
ambiguity in drawing the boundaries of any “waters”:
“[T]he Corps must necessarily choose some point at
which water ends and land begins. Our common ex
perience tells us that this is often no easy task: the
transition from water to solid ground is not necessar
ily or even typically an abrupt one. Rather, between
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Opinion of SCALIA, J.

open waters and dry land may lie shallows, marshes,
mudflats, swamps, bogs—in short, a huge array of ar
eas 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.” Ibid.
Because of this inherent ambiguity, we deferred to the
agency’s inclusion of wetlands “actually abut[ting]” tradi
tional navigable waters: “Faced with such a problem of
defining the bounds of its regulatory authority,” we held,
the agency could reasonably conclude that a wetland that
“adjoin[ed]” waters of the United States is itself a part of
those waters. Id., at 132, 135, and n. 9. The difficulty of
delineating the boundary between water and land was
central to our reasoning in the case: “In view of the
breadth of federal regulatory authority contemplated by
the Act itself and the inherent difficulties of defining pre
cise 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 wa
ters under the Act.” Id., at 134 (emphasis added).10
——————
10 Since the wetlands at issue in Riverside Bayview actually abutted

waters of the United States, the case could not possibly have held that
merely “neighboring” wetlands came within the Corps’ jurisdiction.
Obiter approval of that proposition might be inferred, however, from
the opinion’s quotation without comment of a statement by the Corps
describing covered “adjacent” wetlands as those “ ‘that form the border
of or are in reasonable proximity to other waters of the United States.’ ”
474 U. S., at 134 (quoting 42 Fed. Reg. 37128 (1977); emphasis added).
The opinion immediately reiterated, however, that adjacent wetlands
could be regarded as “the waters of the United States” in view of “the
inherent difficulties of defining precise bounds to regulable waters,” 474
U. S., at 134—a rationale that would have no application to physically
separated “neighboring” wetlands. Given that the wetlands at issue in
Riverside Bayview themselves “actually abut[ted] on a navigable
waterway,” id., at 135; given that our opinion recognized that uncon
nected wetlands could not naturally be characterized as “ ‘waters’ ” at
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When we characterized the holding of Riverside Bayview
in SWANCC, we referred to the close connection between
waters and the wetlands that they gradually blend into:
“It was the significant nexus between the wetlands and
‘navigable waters’ that informed our reading of the CWA
in Riverside Bayview Homes.” 531 U. S., at 167 (emphasis
added). In particular, SWANCC rejected the notion that
the ecological considerations upon which the Corps relied
in Riverside Bayview—and upon which the dissent repeat
edly relies today, see post, at 10–11, 12, 13–14, 15, 18–19,
21–22, 24–25—provided an independent basis for includ
ing entities like “wetlands” (or “ephemeral streams”)
within the phrase “the waters of the United States.”
SWANCC found such ecological considerations irrelevant
to the question whether physically isolated waters come
within the Corps’ jurisdiction. It thus confirmed that
Riverside Bayview rested upon the inherent ambiguity in
defining where water ends and abutting (“adjacent”) wet
lands begin, permitting the Corps’ reliance on ecological
considerations only to resolve that ambiguity in favor of
treating all abutting wetlands as waters. Isolated ponds
were not “waters of the United States” in their own right,
see 531 U. S., at 167, 171, and presented no boundary-
drawing problem that would have justified the invocation
of ecological factors to treat them as such.
Therefore, only those wetlands with a continuous sur
face connection to bodies that are “waters of the United
States” in their own right, so that there is no clear demar
cation between “waters” and wetlands, are “adjacent to”
——————
all, id., at 132; and given the repeated reference to the difficulty of
determining where waters end and wetlands begin; the most natural
reading of the opinion is that a wetlands’ mere “reasonable proximity”
to waters of the United States is not enough to confer Corps jurisdic
tion. In any event, as discussed in our immediately following text, any
possible ambiguity has been eliminated by SWANCC, 531 U. S. 159
(2001).
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Opinion of SCALIA, J.

such waters and covered by the Act. Wetlands with only
an intermittent, physically remote hydrologic connection
to “waters of the United States” do not implicate the
boundary-drawing problem of Riverside Bayview, and thus
lack the necessary connection to covered waters that we
described as a “significant nexus” in SWANCC. 531 U. S.,
at 167. Thus, establishing that wetlands such as those at
the Rapanos and Carabell sites are covered by the Act
requires two findings: First, that the adjacent channel
contains a “wate[r] of the United States,” (i.e., a relatively
permanent body of water connected to traditional inter
state navigable waters); and second, that the wetland has
a continuous surface connection with that water, making
it difficult to determine where the “water” ends and the
“wetland” begins.
V
Respondents and their amici urge that such restrictions
on the scope of “navigable waters” will frustrate enforce
ment against traditional water polluters under 33 U. S. C.
§§1311 and 1342. Because the same definition of “naviga
ble waters” applies to the entire statute, respondents con
tend that water polluters will be able to evade the permit
ting requirement of §1342(a) simply by discharging their
pollutants into noncovered intermittent watercourses that
lie upstream of covered waters. See Tr. of Oral Arg. 74–75.
That is not so. Though we do not decide this issue, there
is no reason to suppose that our construction today signifi
cantly affects the enforcement of §1342, inasmuch as lower
courts applying §1342 have not characterized intermittent
channels as “waters of the United States.” The Act does
not forbid the “addition of any pollutant directly to navi
gable waters from any point source,” but rather the “addi
tion of any pollutant to navigable waters.” §1362(12)(A)
(emphasis added); §1311(a). Thus, from the time of the
CWA’s enactment, lower courts have held that the dis
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Opinion of SCALIA, J.

charge into intermittent channels of any pollutant that
naturally washes downstream likely violates §1311(a),
even if the pollutants discharged from a point source do
not emit “directly into” covered waters, but pass “through
conveyances” in between. United States v. Velsicol Chemi
cal Corp., 438 F. Supp. 945, 946–947 (WD Tenn. 1976) (a
municipal sewer system separated the “point source” and
covered navigable waters). See also Sierra Club v. El Paso
Gold Mines, Inc., 421 F. 3d 1133, 1137, 1141 (CA10 2005)
(2.5 miles of tunnel separated the “point source” and
“navigable waters”).
In fact, many courts have held that such upstream,
intermittently flowing channels themselves constitute
“point sources” under the Act. The definition of “point
source” includes “any pipe, ditch, channel, tunnel, conduit,
well, discrete fissure, container, rolling stock, concentrated
animal feeding operation, or vessel or other floating craft,
from which pollutants are or may be discharged.” 33
U. S. C. §1362(14). We have held that the Act “makes
plain that a point source need not be the original source of
the pollutant; it need only convey the pollutant to ‘naviga
ble waters.’ ” South Fla. Water Management Dist. v. Mic
cosukee Tribe, 541 U. S. 95, 105 (2004). Cases holding the
intervening channel to be a point source include United
States v. Ortiz, 427 F. 3d 1278, 1281 (CA10 2005) (a storm
drain that carried flushed chemicals from a toilet to the
Colorado River was a “point source”), and Dague v. Bur
lington, 935 F. 2d 1343, 1354–1355 (CA2 1991) (a culvert
connecting two bodies of navigable water was a “point
source”), rev’d on other grounds, 505 U. S. 557 (1992).
Some courts have even adopted both the “indirect dis
charge” rationale and the “point source” rationale in the
alternative, applied to the same facts. See, e.g., Concerned
Area Residents for Environment v. Southview Farm, 34
F. 3d 114, 118–119 (CA2 1994). On either view, however,
the lower courts have seen no need to classify the inter
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Opinion of SCALIA, J.

vening conduits as “waters of the United States.”
In contrast to the pollutants normally covered by the
permitting requirement of §1342(a), “dredged or fill mate
rial,” which is typically deposited for the sole purpose of
staying put, does not normally wash downstream,11 and
thus does not normally constitute an “addition . . . to
navigable waters” when deposited in upstream isolated
wetlands. §§1344(a), 1362(12). The Act recognizes this
distinction by providing a separate permitting program for
such discharges in §1344(a). It does not appear, therefore,
that the interpretation we adopt today significantly re
duces the scope of §1342 of the Act.
Respondents also urge that the narrower interpretation
of “waters” will impose a more difficult burden of proof in
enforcement proceedings under §§1311(a) and 1342(a), by
requiring the agency to demonstrate the downstream flow
of the pollutant along the intermittent channel to tradi
——————
11 The dissent argues that “the very existence of words like ‘alluvium’

and ‘silt’ in our language suggests that at least some [dredged or fill
material] makes its way downstream,” post, at 22 (citation omitted).
See also post, at 17 (opinion of KENNEDY, J.). By contrast, amici cite
multiple empirical analyses that contradict the dissent’s philological
approach to sediment erosion—including one which concludes that
“[t]he idea that the discharge of dredged or fill material into isolated
waters, ephemeral drains or non-tidal ditches will pollute navigable
waters located any appreciable distance from them lacks credibility.”
R. Pierce, Technical Principles Related to Establishing the Limits of
Jurisdiction for Section 404 of the Clean Water Act 34–40 (Apr. 2003),
available at www.wetlandtraining.com/tpreljscwa.pdf, cited in Brief for
International Council of Shopping Centers et al. as Amici Curiae 26–27;
Brief for Pulte Homes, Inc., et al. as Amici Curiae 20–21; Brief for
Foundation for Environmental and Economic Progress et al. as Amici
Curiae 29, and n. 53 (“Fill material does not migrate”). Such scientific
analysis is entirely unnecessary, however, to reach the unremarkable
conclusion that the deposit of mobile pollutants into upstream ephem
eral channels is naturally described as an “addition . . . to navigable
waters,” 33 U. S. C. §1362(12), while the deposit of stationary fill
material generally is not.
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Opinion of SCALIA, J.

tional “waters.” See Tr. of Oral Arg. 57. But, as noted
above, the lower courts do not generally rely on charac
terization of intervening channels as “waters of the United
States” in applying §1311 to the traditional pollutants
subject to §1342. Moreover, the proof of downstream flow
of pollutants required under §1342 appears substantially
similar, if not identical, to the proof of a hydrologic connec
tion that would be required, on the Sixth Circuit’s theory
of jurisdiction, to prove that an upstream channel or wet
land is a “wate[r] of the United States.” See Rapanos II,
376 F. 3d, at 639. Compare, e.g., App. to Pet. for Cert. in
No. 04–1034, at B11, B20, B26 (testimony of hydrologic
connections based on observation of surface water connec
tions), with Southview Farm, supra, at 118–121 (testi
mony of discharges based on observation of the flow of
polluted water). In either case, the agency must prove
that the contaminant-laden waters ultimately reach cov
ered waters.
Finally, respondents and many amici admonish that
narrowing the definition of “the waters of the United
States” will hamper federal efforts to preserve the Nation’s
wetlands. It is not clear that the state and local conserva
tion efforts that the CWA explicitly calls for, see 33
U. S. C. §1251(b), are in any way inadequate for the goal
of preservation. In any event, a Comprehensive National
Wetlands Protection Act is not before us, and the
“wis[dom]” of such a statute, post, at 19 (opinion of STE
VENS, J.), is beyond our ken. What is clear, however, is
that Congress did not enact one when it granted the Corps
jurisdiction over only “the waters of the United States.”
VI
In an opinion long on praise of environmental protection
and notably short on analysis of the statutory text and
structure, the dissent would hold that “the waters of the
United States” include any wetlands “adjacent” (no matter
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Opinion of SCALIA, J.

how broadly defined) to “tributaries” (again, no matter
how broadly defined) of traditional navigable waters. For
legal support of its policy-laden conclusion, the dissent
relies exclusively on two sources: “[o]ur unanimous opin
ion in Riverside Bayview,” post, at 6; and “Congress’ delib
erate acquiescence in the Corps’ regulations in 1977,” post,
at 11. Each of these is demonstrably inadequate to sup
port the apparently limitless scope that the dissent would
permit the Corps to give to the Act.
A
The dissent’s assertion that Riverside Bayview “squarely
controls these cases,” post, at 6, is wholly implausible.
First, Riverside Bayview could not possibly support the
dissent’s acceptance of the Corps’ inclusion of dry beds as
“tributaries,” post, at 19, because the definition of tributar
ies was not at issue in that case. Riverside Bayview ad
dressed only the Act’s inclusion of wetlands abutting
navigable-in-fact waters, and said nothing at all about
what non-navigable tributaries the Act might also cover.
Riverside Bayview likewise provides no support for the
dissent’s complacent acceptance of the Corps’ definition of
“adjacent,” which (as noted above) has been extended
beyond reason to include, inter alia, the 100-year flood
plain of covered waters. See supra, at 9. The dissent
notes that Riverside Bayview quoted without comment the
Corps’ description of “adjacent” wetlands as those “that
form the border of or are in reasonable proximity to other
waters of the United States.” Post, at 8 (citing 474 U. S.,
at 134 (quoting 42 Fed. Reg. 37128)). As we have already
discussed, this quotation provides no support for the inclu
sion of physically unconnected wetlands as covered “wa
ters.” See supra, at 22–23, n. 10. The dissent relies prin
cipally on a footnote in Riverside Bayview recognizing that
“ ‘not every adjacent wetland is of great importance to the
environment of adjoining bodies of water,’ ” and that all
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Opinion of SCALIA, J.

“ ‘adjacent’ ” wetlands are nevertheless covered by the Act,
post, at 8 (quoting 474 U. S., at 135, n. 9). Of course, this
footnote says nothing to support the dissent’s broad defini
tion of “adjacent”—quite the contrary, the quoted sentence
uses “adjacent” and “adjoining” interchangeably, and the
footnote qualifies a sentence holding that the wetland was
covered “[b]ecause” it “actually abut[ted] on a navigable
waterway.” Id., at 135 (emphasis added). Moreover, that
footnote’s assertion that the Act may be interpreted to
include even those adjoining wetlands that are “lacking in
importance to the aquatic environment,” id., at 135, n. 9,
confirms that the scope of ambiguity of “the waters of the
United States” is determined by a wetland’s physical con
nection to covered waters, not its ecological relationship
thereto.
The dissent reasons (1) that Riverside Bayview held that
“the waters of the United States” include “adjacent wet
lands,” and (2) we must defer to the Corps’ interpretation
of the ambiguous word “adjacent.” Post, at 20–21. But
this is mere legerdemain. The phrase “adjacent wetlands”
is not part of the statutory definition that the Corps is
authorized to interpret, which refers only to “the waters of
the United States,” 33 U. S. C. §1362(7).12 In expounding
the term “adjacent” as used in Riverside Bayview, we are
explaining our own prior use of that word to interpret the
definitional phrase “the waters of the United States.”
——————
12 Nor does the passing reference to “wetlands adjacent thereto” in
§1344(g)(1) purport to expand that statutory definition. As the dissent
concedes, post, at 20, that reference merely confirms that the statutory
definition can be read to include some wetlands—namely, those that
directly “abut” covered waters. Riverside Bayview explicitly acknowl
edged that §1344(g)(1) “does not conclusively determine the construc
tion to be placed on the use of the term ‘waters’ elsewhere in the Act
(particularly in [§1362(7)], which contains the relevant definition of
‘navigable waters’); however, . . . it does at least suggest strongly that
the term ‘waters’ as used in the Act does not necessarily exclude ‘wet
lands.’ ” 474 U. S., at 138, n. 11 (emphases added).
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Opinion of SCALIA, J.

However ambiguous the term may be in the abstract, as
we have explained earlier, “adjacent” as used in Riverside
Bayview is not ambiguous between “physically abutting”
and merely “nearby.” See supra, at 21–23.
The dissent would distinguish SWANCC on the ground
that it “had nothing to say about wetlands,” post, at 9—
i.e., it concerned “isolated ponds” rather than isolated
wetlands. This is the ultimate distinction without a dif
ference. If isolated “permanent and seasonal ponds of
varying size . . . and depth,” 531 U. S., at 163—which,
after all, might at least be described as “waters” in their
own right—did not constitute “waters of the United
States,” a fortiori, isolated swampy lands do not constitute
“waters of the United States.” See also 474 U. S., at 132.
As the author of today’s dissent has written, “[i]f, as I
believe, actually navigable waters lie at the very heart of
Congress’ commerce power and ‘isolated,’ nonnavigable
waters lie closer to . . . the margin, ‘isolated wetlands,’
which are themselves only marginally ‘waters,’ are the
most marginal category of ‘waters of the United States’
potentially covered by the statute.” 531 U. S., at 187,
n. 13 (STEVENS, J., dissenting).
The only other ground that the dissent offers to distin
guish SWANCC is that, unlike the ponds in SWANCC, the
wetlands in these cases are “adjacent to navigable bodies
of water and their tributaries”—where “adjacent” may be
interpreted who-knows-how broadly. It is not clear why
roughly defined physical proximity should make such a
difference—without actual abutment, it raises no bound
ary-drawing ambiguity, and it is undoubtedly a poor proxy
for ecological significance. In fact, though the dissent is
careful to restrict its discussion to wetlands “adjacent” to
tributaries, its reasons for including those wetlands are
strictly ecological—such wetlands would be included be
cause they “serve . . . important water quality roles,” post,
at 11, and “play important roles in the watershed,” post, at
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Opinion of SCALIA, J.

18–19. This reasoning would swiftly overwhelm SWANCC
altogether; after all, the ponds at issue in SWANCC could,
no less than the wetlands in these cases, “offer ‘nesting,
spawning, rearing and resting sites for aquatic or land
species,’ ” and “ ‘serve as valuable storage areas for storm
and flood waters,’ ” post, at 9–10. The dissent’s exclusive
focus on ecological factors, combined with its total deference
to the Corps’ ecological judgments, would permit the Corps
to regulate the entire country as “waters of the United
States.”
B
Absent a plausible ground in our case law for its sweep
ing position, the dissent relies heavily on “Congress’ delib
erate acquiescence in the Corps’ regulations in 1977,” post,
at 11—noting that “[w]e found [this acquiescence] signifi
cant in Riverside Bayview,” and even “acknowledged in
SWANCC” that we had done so, post, at 12. SWANCC
“acknowledged” that Riverside Bayview had relied on
congressional acquiescence only to criticize that reliance.
It reasserted in no uncertain terms our oft-expressed
skepticism towards reading the tea leaves of congressional
inaction:
“Although we have recognized congressional acquies
cence to administrative interpretations of a statute in
some situations, we have done so with extreme care.
Failed legislative proposals are a particularly danger
ous ground on which to rest an interpretation of a
prior statute. . . . The relationship between the actions
and inactions of the 95th Congress and the intent of
the 92d Congress in passing [§1344(a)] is also consid
erably attenuated. Because subsequent history is less
illuminating than the contemporaneous evidence, re
spondents face a difficult task in overcoming the plain
text and import of [§1344(a)].” 531 U. S., at 169 (cita
tions, internal quotation marks, and footnote omitted).
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Congress takes no governmental action except by legis
lation. What the dissent refers to as “Congress’ deliberate
acquiescence” should more appropriately be called Con
gress’s failure to express any opinion. We have no idea
whether the Members’ failure to act in 1977 was attribut
able to their belief that the Corps’ regulations were cor
rect, or rather to their belief that the courts would elimi
nate any excesses, or indeed simply to their unwillingness
to confront the environmental lobby. To be sure, we have
sometimes relied on congressional acquiescence when
there is evidence that Congress considered and rejected
the “precise issue” presented before the Court, Bob Jones
Univ. v. United States, 461 U. S. 574, 600 (1983) (empha
sis added). However, “[a]bsent such overwhelming evi
dence of acquiescence, we are loath to replace the plain
text and original understanding of a statute with an
amended agency interpretation.” SWANCC, supra, at 169,
n. 5 (emphasis added).
The dissent falls far short of producing “overwhelming
evidence” that Congress considered and failed to act upon
the “precise issue” before the Court today—namely, what
constitutes an “adjacent” wetland covered by the Act.
Citing Riverside Bayview’s account of the 1977 debates,
the dissent claims nothing more than that Congress “con
ducted extensive debates about the Corps’ regulatory
jurisdiction over wetlands [and] rejected efforts to limit
that jurisdiction . . . .” Post, at 11. In fact, even that
vague description goes too far. As recounted in Riverside
Bayview, the 1977 debates concerned a proposal to “limi[t]
the Corps’ authority under [§1344] to waters navigable in
fact and their adjacent wetlands (defined as wetlands
periodically inundated by contiguous navigable waters),”
474 U. S., at 136. In rejecting this proposal, Congress
merely failed to enact a limitation of “waters” to include
only navigable-in-fact waters—an interpretation we af
firmatively reject today, see supra, at 12—and a definition
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of wetlands based on “periodi[c] inundat[ion]” that appears
almost nowhere in the briefs or opinions of these cases.13
No plausible interpretation of this legislative inaction can
construe it as an implied endorsement of every jot and
tittle of the Corps’ 1977 regulations. In fact, Riverside
Bayview itself relied on this legislative inaction only as “at
least some evidence of the reasonableness” of the agency’s
inclusion of adjacent wetlands under the Act, 474 U. S., at
137, and for the observation that “even those who would
have restricted the reach of the Corps’ jurisdiction” would
not have excised adjacent wetlands, ibid. Both of these
——————
13 The sole exception is in JUSTICE KENNEDY’s opinion, which argues

that Riverside Bayview rejected our physical-connection requirement by
accepting as a given that any wetland formed by inundation from
covered waters (whether or not continuously connected to them) is
covered by the Act: “The Court in Riverside Bayview . . . did not suggest
that a flood-based origin would not support jurisdiction; indeed, it
presumed the opposite. See 474 U. S., at 134 (noting that the Corps’
view was valid ‘even for wetlands that are not the result of flooding or
permeation’ (emphasis added)).” Post, at 16. Of course JUSTICE
KENNEDY himself fails to observe this supposed presumption, since his
“significant nexus” test makes no exception for wetlands created by
inundation. In any event, the language from Riverside Bayview in
JUSTICE KENNEDY’s parenthetical is wrenched out of context. The
sentence which JUSTICE KENNEDY quotes in part immediately followed
the Court’s conclusion that “adjacent” wetlands are included because of
“the inherent difficulties of defining precise bounds to regulable wa
ters,” 474 U. S., at 134. And the full sentence reads as follows: “This
holds true even for wetlands that are not the result of flooding or
permeation by water having its source in adjacent bodies of open
water,” ibid. (emphasis added). Clearly, the “wetlands” referred to in
the sentence are only “adjacent” wetlands—namely, those with the
continuous physical connection that the rest of the Riverside Bayview
opinion required, see supra, at 21–23. Thus, it is evident that the
quoted language was not at all a rejection of the physical-connection
requirement, but rather a rejection of the alternative position (which
had been adopted by the lower court in that case, see id., at 125) that
the only covered wetlands are those created by inundation. As long as
the wetland is “adjacent” to covered waters, said Riverside Bayview, its
creation vel non by inundation is irrelevant.
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Opinion of SCALIA, J.

conclusions are perfectly consistent with our interpreta
tion, and neither illuminates the disputed question of
what constitutes an “adjacent” wetland.
C
In a curious appeal to entrenched Executive error, the
dissent contends that “the appropriateness of the Corps’
30-year implementation of the Clean Water Act should be
addressed to Congress or the Corps rather than to the
Judiciary.” Post, at 14; see also post, at 2, 22. Surely this
is a novel principle of administrative law—a sort of 30
year adverse possession that insulates disregard of statu
tory text from judicial review. It deservedly has no prece
dent in our jurisprudence. We did not invoke such a prin
ciple in SWANCC, when we invalidated one aspect of the
Corps’ implementation.
The dissent contends that “[b]ecause there is ambiguity
in the phrase ‘waters of the United States’ and because
interpreting it broadly to cover such ditches and streams
advances the purpose of the Act, the Corps’ approach
should command our deference.” Post, at 19. Two defects
in a single sentence: “[W]aters of the United States” is in
some respects ambiguous. The scope of that ambiguity,
however, does not conceivably extend to whether storm
drains and dry ditches are “waters,” and hence does not
support the Corps’ interpretation. And as for advancing
“the purpose of the Act”: We have often criticized that last
resort of extravagant interpretation, noting that no law
pursues its purpose at all costs, and that the textual limi
tations upon a law’s scope are no less a part of its “pur
pose” than its substantive authorizations. See, e.g., Direc
tor, Office of Workers’ Compensation Programs v. Newport
News Shipbuilding & Dry Dock Co., 514 U. S. 122, 135–
136 (1995).
Finally, we could not agree more with the dissent’s
statement, post, at 14, that “[w]hether the benefits of
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Opinion of SCALIA, J.

particular conservation measures outweigh their costs is a
classic question of public policy that should not be an
swered by appointed judges.” Neither, however, should it
be answered by appointed officers of the Corps of Engi
neers in contradiction of congressional direction. It is the
dissent’s opinion, and not ours, which appeals not to a
reasonable interpretation of enacted text, but to the great
environmental benefits that a patently unreasonable
interpretation can achieve. We have begun our discussion
by mentioning, to be sure, the high costs imposed by that
interpretation—but they are in no way the basis for our
decision, which rests, plainly and simply, upon the limited
meaning that can be borne by the phrase “waters of the
United States.”
VII
JUSTICE KENNEDY’s opinion concludes that our reading
of the Act “is inconsistent with its text, structure, and
purpose.” Post, at 19. His own opinion, however, leaves
the Act’s “text” and “structure” virtually unaddressed, and
rests its case upon an interpretation of the phrase “signifi
cant nexus,” ibid., which appears in one of our opinions.
To begin with, JUSTICE KENNEDY’s reading of “signifi
cant nexus” bears no easily recognizable relation to either
the case that used it (SWANCC) or to the earlier case that
that case purported to be interpreting (Riverside Bayview).
To establish a “significant nexus,” JUSTICE KENNEDY
would require the Corps to “establish . . . on a case-by-case
basis” that wetlands adjacent to nonnavigable tributaries
“significantly affect the chemical, physical, and biological
integrity of other covered waters more readily understood
as ‘navigable.’ ” Post, at 25, 23. This standard certainly
does not come from Riverside Bayview, which explicitly
rejected such case-by-case determinations of ecological
significance for the jurisdictional question whether a
wetland is covered, holding instead that all physically
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Opinion of SCALIA, J.

connected wetlands are covered. 474 U. S., at 135, n. 9. It
is true enough that one reason for accepting that physical-
connection criterion was the likelihood that a physically
connected wetland would have an ecological effect upon
the adjacent waters. But case-by-case determination of
ecological effect was not the test. Likewise, that test can
not be derived from SWANCC’s characterization of River
side Bayview, which emphasized that the wetlands which
possessed a “significant nexus” in that earlier case “actu
ally abutted on a navigable waterway,” 531 U. S., at 167,
and which specifically rejected the argument that physi
cally unconnected ponds could be included based on their
ecological connection to covered waters. In fact, JUSTICE
KENNEDY acknowledges that neither Riverside Bayview
nor SWANCC required, for wetlands abutting navigable-
in-fact waters, the case-by-case ecological determination
that he proposes for wetlands that neighbor nonnavigable
tributaries. See post, at 23. Thus, JUSTICE KENNEDY
misreads SWANCC’s “significant nexus” statement as
mischaracterizing Riverside Bayview to adopt a case-by
case test of ecological significance; and then transfers that
standard to a context that Riverside Bayview expressly
declined to address (namely, wetlands nearby non
navigable tributaries); while all the time conceding that
this standard does not apply in the context that Riverside
Bayview did address (wetlands abutting navigable water
ways). Truly, this is “turtles all the way down.”14

——————
14 The allusion is to a classic story told in different forms and attrib

uted to various authors. See, e.g., Geertz, Thick Description: Toward
an Interpretive Theory of Culture, in The Interpretation of Cultures
28–29 (1973). In our favored version, an Eastern guru affirms that the
earth is supported on the back of a tiger. When asked what supports
the tiger, he says it stands upon an elephant; and when asked what
supports the elephant he says it is a giant turtle. When asked, finally,
what supports the giant turtle, he is briefly taken aback, but quickly
replies “Ah, after that it is turtles all the way down.”
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But misreading our prior decisions is not the principal
problem. The principal problem is reading them in utter
isolation from the text of the Act. One would think, after
reading JUSTICE KENNEDY’s exegesis, that the crucial
provision of the text of the CWA was a jurisdictional re
quirement of “significant nexus” between wetlands and
navigable waters. In fact, however, that phrase appears
nowhere in the Act, but is taken from SWANCC’s cryptic
characterization of the holding of Riverside Bayview. Our
interpretation of the phrase is both consistent with those
opinions and compatible with what the Act does establish
as the jurisdictional criterion: “waters of the United
States.” Wetlands are “waters of the United States” if
they bear the “significant nexus” of physical connection,
which makes them as a practical matter indistinguishable
from waters of the United States. What other nexus could
conceivably cause them to be “waters of the United
States”? JUSTICE KENNEDY’s test is that they, “either
alone or in combination with similarly situated lands in
the region, significantly affect the chemical, physical, and
biological integrity of other covered waters more readily
understood as ‘navigable,’ ” post, at 23 (emphasis added).
But what possible linguistic usage would accept that
whatever (alone or in combination) affects waters of the
United States is waters of the United States?
Only by ignoring the text of the statute and by assuming
that the phrase of SWANCC (“significant nexus”) can
properly be interpreted in isolation from that text does
JUSTICE KENNEDY reach the conclusion he has arrived at.
Instead of limiting its meaning by reference to the text it
was applying, he purports to do so by reference to what he
calls the “purpose” of the statute. Its purpose is to clean
up the waters of the United States, and therefore anything
that might “significantly affect” the purity of those waters
bears a “significant nexus” to those waters, and thus (he
never says this, but the text of the statute demands that
38 RAPANOS v. UNITED STATES

Opinion of SCALIA, J.

he mean it) is those waters. This is the familiar tactic of
substituting the purpose of the statute for its text, freeing
the Court to write a different statute that achieves the
same purpose. To begin with, as we have discussed ear
lier, clean water is not the only purpose of the statute. So
is the preservation of primary state responsibility for
ordinary land-use decisions. 33 U. S. C. §1251(b).
JUSTICE KENNEDY’s test takes no account of this purpose.
More fundamentally, however, the test simply rewrites the
statute, using for that purpose the gimmick of “significant
nexus.” It would have been an easy matter for Congress to
give the Corps jurisdiction over all wetlands (or, for that
matter, all dry lands) that “significantly affect the chemi
cal, physical, and biological integrity of ” waters of the
United States. It did not do that, but instead explicitly
limited jurisdiction to “waters of the United States.”
JUSTICE KENNEDY’s disposition would disallow some of
the Corps’ excesses, and in that respect is a more moder
ate flouting of statutory command than JUSTICE
STEVENS’.15 In another respect, however, it is more ex
treme. At least JUSTICE STEVENS can blame his implausi
ble reading of the statute upon the Corps. His error con

——————
15 It is unclear how much more moderate the flouting is, since JUSTICE

KENNEDY’s “significant nexus” standard is perfectly opaque. When,
exactly, does a wetland “significantly affect” covered waters, and when
are its effects “in contrast . . . speculative or insubstantial”? Post, at 23.
JUSTICE KENNEDY does not tell us clearly—except to suggest, post, at
25, that “ ‘ “isolated” is generally a matter of degree’ ” (quoting Lei
bowitz & Nadeau, Isolated Wetlands: State-of-the-Science and Future
Directions, 23 Wetlands 663, 669 (2003)). As the dissent hopefully
observes, post, at 24, such an unverifiable standard is not likely to
constrain an agency whose disregard for the statutory language has
been so long manifested. In fact, by stating that “[i]n both the consoli
dated cases before the Court the record contains evidence suggesting
the possible existence of a significant nexus according to the principles
outlined above,” post, at 26, JUSTICE KENNEDY tips a wink at the
agency, inviting it to try its same expansive reading again.
 Cite as: 547 U. S. ____ (2006) 39

Opinion of SCALIA, J.

sists of giving that agency more deference than reason
permits. JUSTICE KENNEDY, however, has devised his new
statute all on his own. It purports to be, not a grudging
acceptance of an agency’s close-to-the-edge expansion of its
own powers, but rather the most reasonable interpretation
of the law. It is far from that, unless whatever affects
waters is waters.
VIII
Because the Sixth Circuit applied the wrong standard to
determine if these wetlands are covered “waters of the
United States,” and because of the paucity of the record in
both of these cases, the lower courts should determine, in
the first instance, whether the ditches or drains near each
wetland are “waters” in the ordinary sense of containing a
relatively permanent flow; and (if they are) whether the
wetlands in question are “adjacent” to these “waters” in
the sense of possessing a continuous surface connection
that creates the boundary-drawing problem we addressed
in Riverside Bayview.
* * *
We vacate the judgments of the Sixth Circuit in both
No. 04–1034 and No. 04–1384, and remand both cases for
further proceedings.

It is so ordered.
 Cite as: 547 U. S. ____ (2006) 1

ROBERTS, C. J., concurring

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 04–1034 and 04–1384
_________________

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS
04–1034 v.
UNITED STATES

JUNE CARABELL ET AL., PETITIONERS
04–1384 v.
UNITED STATES ARMY CORPS OF ENGINEERS ET AL.
ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE SIXTH CIRCUIT
[June 19, 2006]

CHIEF JUSTICE ROBERTS, concurring.
Five years ago, this Court rejected the position of the
Army Corps of Engineers on the scope of its authority to
regulate wetlands under the Clean Water Act, 86 Stat.
816, as amended, 33 U. S. C. §1251 et seq. Solid Waste
Agency of Northern Cook Cty. v. Army Corps of Engineers,
531 U. S. 159 (2001) (SWANCC). The Corps had taken the
view that its authority was essentially limitless; this
Court explained that such a boundless view was inconsis
tent with the limiting terms Congress had used in the Act.
Id., at 167–174.
In response to the SWANCC decision, the Corps and the
Environmental Protection Agency (EPA) initiated a rule-
making to consider “issues associated with the scope of
waters that are subject to the Clean Water Act (CWA), in
light of the U. S. Supreme Court decision in [SWANCC].”
68 Fed. Reg. 1991 (2003). The “goal of the agencies” was
“to develop proposed regulations that will further the
public interest by clarifying what waters are subject to
2 RAPANOS v. UNITED STATES

ROBERTS, C. J., concurring

CWA jurisdiction and affording full protection to these
waters through an appropriate focus of Federal and State
resources consistent with the CWA.” Ibid.
Agencies delegated rulemaking authority under a stat
ute such as the Clean Water Act are afforded generous
leeway by the courts in interpreting the statute they are
entrusted to administer. See Chevron U. S. A. Inc. v. Natu
ral Resources Defense Council, Inc., 467 U. S. 837, 842–845
(1984). Given the broad, somewhat ambiguous, but none
theless clearly limiting terms Congress employed in the
Clean Water Act, the Corps and the EPA would have en
joyed plenty of room to operate in developing some notion of
an outer bound to the reach of their authority.
The proposed rulemaking went nowhere. Rather than
refining its view of its authority in light of our decision in
SWANCC, and providing guidance meriting deference under
our generous standards, the Corps chose to adhere to its
essentially boundless view of the scope of its power. The
upshot today is another defeat for the agency.
It is unfortunate that no opinion commands a majority of
the Court on precisely how to read Congress’ limits on the
reach of the Clean Water Act. Lower courts and regulated
entities will now have to feel their way on a case-by-case
basis. This situation is certainly not unprecedented. See
Grutter v. Bollinger, 539 U. S. 306, 325 (2003) (discussing
Marks v. United States, 430 U. S. 188 (1977)). What is
unusual in this instance, perhaps, is how readily the situa
tion could have been avoided.*
——————
* The scope of the proposed rulemaking was not as narrow as JUSTICE
STEVENS suggests, post, at 10, n. 4 (dissenting opinion). See 68 Fed.
Reg. 1994 (2003) (“Additionally, we invite your views as to whether any
other revisions are needed to the existing regulations on which waters
are jurisdictional under the CWA”); id., at 1992 (“Today’s [notice of
proposed rulemaking] seeks public input on what, if any, revisions in
light of SWANCC might be appropriate to the regulations that define
‘waters of the U. S.’, and today’s [notice] thus would be of interest to all
 Cite as: 547 U. S. ____ (2006) 3

ROBERTS, C. J., concurring

——————

entities discharging to, or regulating, such waters” (emphases added)).

The agencies can decide for themselves whether, as the SWANCC

dissenter suggests, it was wise for them to take no action in response to

SWANCC.
 Cite as: 547 U. S. ____ (2006) 1

KENNEDY, J., concurring in judgment

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 04–1034 and 04–1384
_________________

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS
04–1034 v.
UNITED STATES

JUNE CARABELL ET AL., PETITIONERS
04–1384 v.
UNITED STATES ARMY CORPS OF ENGINEERS ET AL.

ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE SIXTH CIRCUIT

[June 19, 2006]

JUSTICE KENNEDY, concurring in the judgment.
These consolidated cases require the Court to decide
whether the term “navigable waters” in the Clean Water
Act extends to wetlands that do not contain and are not
adjacent to waters that are navigable in fact. In Solid
Waste Agency of Northern Cook Cty. v. Army Corps of Engi
neers, 531 U. S. 159 (2001) (SWANCC), the Court held,
under the circumstances presented there, that to consti
tute “ ‘navigable waters’ ” under the Act, a water or wet
land must possess a “significant nexus” to waters that are
or were navigable in fact or that could reasonably be so
made. Id., at 167, 172. In the instant cases neither the
plurality opinion nor the dissent by JUSTICE STEVENS
chooses to apply this test; and though the Court of Appeals
recognized the test’s applicability, it did not consider all
the factors necessary to determine whether the lands in
2 RAPANOS v. UNITED STATES

KENNEDY, J., concurring in judgment

question had, or did not have, the requisite nexus. In my
view the cases ought to be remanded to the Court of Ap
peals for proper consideration of the nexus requirement.
I
Although both the plurality opinion and the dissent by
JUSTICE STEVENS (hereinafter the dissent) discuss the
background of these cases in some detail, a further discus
sion of the relevant statutes, regulations, and facts may
clarify the analysis suggested here.
A
The “objective” of the Clean Water Act (Act), is “to restore
and maintain the chemical, physical, and biological integ
rity of the Nation’s waters.” 33 U. S. C. §1251(a). To that
end, the statute, among other things, prohibits “the dis
charge of any pollutant by any person” except as provided
in the Act. §1311(a). As relevant here, the term “discharge
of a pollutant” means “any addition of any pollutant to
navigable waters from any point source.” §1362(12). The
term “pollutant” is defined as “dredged spoil, solid waste,
incinerator residue, sewage, garbage, sewage sludge, muni
tions, chemical wastes, biological materials, radioactive
materials, heat, wrecked or discarded equipment, rock,
sand, cellar dirt and industrial, municipal, and agricultural
waste discharged into water.” §1362(6). The Secretary of
the Army, acting through the Chief of Engineers of the
Army Corps of Engineers, may issue permits for “discharge
of dredged or fill material into the navigable waters at
specified disposal sites.” §§1344(a), (c), (d); but see §1344(f)
(categorically exempting certain forms of “discharge of
dredged or fill material” from regulation under §1311(a)).
Pursuant to §1344(g), States with qualifying programs may
assume certain aspects of the Corps’ permitting responsibil
ity. Apart from dredged or fill material, pollutant dis
charges require a permit from the Environmental Protec
 Cite as: 547 U. S. ____ (2006) 3

KENNEDY, J., concurring in judgment

tion Agency (EPA), which also oversees the Corps’ (and
qualifying States’) permitting decisions. See §§1311(a),
1342(a), 1344(c). Discharge of pollutants without an appro
priate permit may result in civil or criminal liability. See
§1319.
The statutory term to be interpreted and applied in the
two instant cases is the term “navigable waters.” The
outcome turns on whether that phrase reasonably de
scribes certain Michigan wetlands the Corps seeks to
regulate. Under the Act “[t]he term ‘navigable waters’
means the waters of the United States, including the
territorial seas.” §1362(7). In a regulation the Corps has
construed the term “waters of the United States” to in
clude not only waters susceptible to use in interstate
commerce—the traditional understanding of the term
“navigable waters of the United States,” see, e.g., United
States v. Appalachian Elec. Power Co., 311 U. S. 377, 406–
408 (1940); The Daniel Ball, 10 Wall. 557, 563–564 (1871)—
but also tributaries of those waters and, of particular rele
vance here, wetlands adjacent to those waters or their tribu
taries. 33 CFR §§328.3(a)(1), (5), (7) (2005). The Corps
views tributaries as within its jurisdiction if they carry a
perceptible “ordinary high water mark.” §328.4(c); 65 Fed.
Reg. 12823 (2000). An ordinary high-water mark is a “line
on the shore established by the fluctuations of water and
indicated by physical characteristics such as clear, natural
line impressed on the bank, shelving, changes in the char
acter of soil, destruction of terrestrial vegetation, the
presence of litter and debris, or other appropriate means
that consider the characteristics of the surrounding ar
eas.” 33 CFR §328.3(e).
Contrary to the plurality’s description, ante, at 2–3, 15,
wetlands are not simply moist patches of earth. They are
defined as “those areas that are inundated or saturated by
surface or ground water at a frequency and duration suffi
cient to support, and that under normal circumstances do
4 RAPANOS v. UNITED STATES

KENNEDY, J., concurring in judgment

support, a prevalence of vegetation typically adapted for life
in saturated soil conditions. Wetlands generally include
swamps, marshes, bogs, and similar areas.” §328.3(b). The
Corps’ Wetlands Delineation Manual, including over 100
pages of technical guidance for Corps officers, interprets
this definition of wetlands to require: (1) prevalence of plant
species typically adapted to saturated soil conditions, de
termined in accordance with the United States Fish and
Wildlife Service’s National List of Plant Species that Occur
in Wetlands; (2) hydric soil, meaning soil that is saturated,
flooded, or ponded for sufficient time during the growing
season to become anaerobic, or lacking in oxygen, in the
upper part; and (3) wetland hydrology, a term generally
requiring continuous inundation or saturation to the sur
face during at least five percent of the growing season in
most years. See Wetlands Research Program Technical
Report Y–87–1 (on-line edition), pp. 12–34 (Jan. 1987),
http://www.saj.usace.army.mil/permit/documents/87manual
.pdf (all Internet material as visited June 16, 2006, and
available in Clerk of Court’s case file). Under the Corps’
regulations, wetlands are adjacent to tributaries, and thus
covered by the Act, even if they are “separated from other
waters of the United States by man-made dikes or barriers,
natural river berms, beach dunes and the like.” §328.3(c).
B
The first consolidated case before the Court, Rapanos v.
United States, No. 04–1034, relates to a civil enforcement
action initiated by the United States in the United States
District Court for the Eastern District of Michigan against
the owners of three land parcels near Midland, Michigan.
The first parcel, known as the Salzburg site, consists of
roughly 230 acres. The District Court, applying the Corps’
definition of wetlands, found based on expert testimony
that the Salzburg site included 28 acres of wetlands. The
District Court further found that “the Salzburg wetlands
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KENNEDY, J., concurring in judgment

have a surface water connection to tributaries of the
Kawkawlin River which, in turn, flows into the Saginaw
River and ultimately into Lake Huron.” App. to Pet. for
Cert. B11. Water from the site evidently spills into the
Hoppler Drain, located just north of the property, which
carries water into the Hoppler Creek and thence into the
Kawkawlin River, which is navigable. A state official
testified that he observed carp spawning in a ditch just
north of the property, indicating a direct surface-water
connection from the ditch to the Saginaw Bay of Lake
Huron.
The second parcel, known as the Hines Road site, con
sists of 275 acres, which the District Court found included
64 acres of wetlands. The court found that the wetlands
have a surface-water connection to the Rose Drain, which
carries water into the Tittabawassee River, a navigable
waterway. The final parcel, called the Pine River site,
consists of some 200 acres. The District Court found that
49 acres were wetlands and that a surface water connec
tion linked the wetlands to the nearby Pine River, which
flows into Lake Huron.
At all relevant times, John Rapanos owned the Salzburg
site; a company he controlled owned the Hines Road site;
and Rapanos’ wife and a company she controlled (possibly
in connection with another entity) owned the Pine River
site. All these parties are petitioners here. In December
1988, Mr. Rapanos, hoping to construct a shopping center,
asked the Michigan Department of Natural Resources to
inspect the Salzburg site. A state official informed Ra
panos that while the site likely included regulated wet
lands, Rapanos could proceed with the project if the wet
lands were delineated (that is, identified and preserved) or
if a permit were obtained. Pursuing the delineation op
tion, Rapanos hired a wetlands consultant to survey the
property. The results evidently displeased Rapanos:
Informed that the site included between 48 and 58 acres of
6 RAPANOS v. UNITED STATES

KENNEDY, J., concurring in judgment

wetlands, Rapanos allegedly threatened to “destroy” the
consultant unless he eradicated all traces of his report.
Rapanos then ordered $350,000-worth of earthmoving and
landclearing work that filled in 22 of the 64 wetlands
acres on the Salzburg site. He did so without a permit and
despite receiving cease-and-desist orders from state offi
cials and the EPA. At the Hines Road and Pine River
sites, construction work—again conducted in violation of
state and federal compliance orders—altered an additional
17 and 15 wetlands acres, respectively.
The Federal Government brought criminal charges
against Rapanos. In the suit at issue here, however, the
United States alleged civil violations of the Clean Water
Act against all the Rapanos petitioners. Specifically, the
Government claimed that petitioners discharged fill into
jurisdictional wetlands, failed to respond to requests for
information, and ignored administrative compliance or
ders. See 33 U. S. C. §§1311(a), 1318(a), 1319(a). After a
13-day bench trial, the District Court made the findings
noted earlier and, on that basis, upheld the Corps’ juris
diction over wetlands on the three parcels. On the merits
the court ruled in the Government’s favor, finding that
violations occurred at all three sites. As to two other sites,
however, the court rejected the Corps’ claim to jurisdic
tion, holding that the Government had failed to carry its
burden of proving the existence of wetlands under the
three-part regulatory definition. (These two parcels are no
longer at issue.) The United States Court of Appeals for
the Sixth Circuit affirmed. 376 F. 3d 629, 634 (2004).
This Court granted certiorari to consider the Corps’ juris
diction over wetlands on the Salzburg, Hines Road, and
Pine River sites. 546 U. S. ___ (2005).
The second consolidated case, Carabell, No. 04–1384,
involves a parcel shaped like a right triangle and consist
ing of some 19.6 acres, 15.9 of which are forested wet
lands. 257 F. Supp. 2d 917, 923 (ED Mich. 2003). The
 Cite as: 547 U. S. ____ (2006) 7

KENNEDY, J., concurring in judgment

property is located roughly one mile from Lake St. Clair, a
430-square-mile lake located between Michigan and Can
ada that is popular for boating and fishing and produces
some 48 percent of the sport fish caught in the Great
Lakes, see Brief for Macomb County, Michigan as Amicus
Curiae 2. The right-angle corner of the property is located
to the northwest. The hypotenuse, which runs from north
east to southwest, lies alongside a man-made berm that
separates the property from a ditch. At least under cur
rent conditions—that is, without the deposit of fill in the
wetlands that the landowners propose—the berm ordinar
ily, if not always, blocks surface-water flow from the wet
lands into the ditch. But cf. App. 186a (administrative
hearing testimony by consultant for Carabells indicating
“you would start seeing some overflow” in a “ten year
storm”). Near the northeast corner of the property, the
ditch connects with the Sutherland-Oemig Drain, which
carries water continuously throughout the year and emp
ties into Auvase Creek. The creek in turn empties into
Lake St. Clair. At its southwest end, the ditch connects to
other ditches that empty into the Auvase Creek and
thence into Lake St. Clair.
In 1993 petitioners Keith and June Carabell sought a
permit from the Michigan Department of Environmental
Quality (MDEQ), which has assumed permitting functions
of the Corps pursuant to §1344(g). Petitioners hoped to fill
in the wetlands and construct 130 condominium units.
Although the MDEQ denied the permit, a State Adminis
trative Law Judge directed the agency to approve an
alternative plan, proposed by the Carabells, that involved
the construction of 112 units. This proposal called for
filling in 12.2 acres of the property while creating reten
tion ponds on 3.74 acres. Because the EPA had objected to
the permit, jurisdiction over the case transferred to the
Corps. See §1344(j).
The Corps’ district office concluded that the Carabells’
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KENNEDY, J., concurring in judgment

property “provides water storage functions that, if de
stroyed, could result in an increased risk of erosion and
degradation of water quality in the Sutherland-Oemig
Drain, Auvase Creek, and Lake St. Clair.” Id., at 127a.
The district office denied the permit, and the Corps upheld
the denial in an administrative appeal. The Carabells,
challenging both the Corps’ jurisdiction and the merits of
the permit denial, sought judicial review pursuant to the
Administrative Procedure Act, 5 U. S. C. §706(2)(A). The
United States District Court for the Eastern District of
Michigan granted summary judgment to the Corps, 257
F. Supp. 2d 917, and the United States Court of Appeals
for the Sixth Circuit affirmed, 391 F. 3d 704 (2005). This
Court granted certiorari to consider the jurisdictional
question. 546 U. S. ___ (2005).
II
Twice before the Court has construed the term “navigable
waters” in the Clean Water Act. In United States v. River
side Bayview Homes, Inc., 474 U. S. 121 (1985), the Court
upheld the Corps’ jurisdiction over wetlands adjacent to
navigable-in-fact waterways. Id., at 139. The property in
Riverside Bayview, like the wetlands in the Carabell case
now before the Court, was located roughly one mile from
Lake St. Clair, see United States v. Riverside Bayview
Homes, Inc., 729 F. 2d 391, 392 (CA6 1984) (decision on
review in Riverside Bayview), though in that case, unlike
Carabell, the lands at issue formed part of a wetland that
directly abutted a navigable-in-fact creek, 474 U. S., at 131.
In regulatory provisions that remain in effect, the Corps
had concluded that wetlands perform important functions
such as filtering and purifying water draining into adjacent
water bodies, 33 CFR §320.4(b)(2)(vii), slowing the flow of
runoff into lakes, rivers, and streams so as to prevent flood
ing and erosion, §§320.4(b)(2)(iv), (v), and providing critical
habitat for aquatic animal species, §320.4(b)(2)(i). 474
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KENNEDY, J., concurring in judgment

U. S., at 134–135. Recognizing that “[a]n agency’s construc
tion of a statute it is charged with enforcing is entitled to
deference if it is reasonable and not in conflict with the
expressed intent of Congress,” id., at 131 (citing Chemical
Mfrs. Assn. v. Natural Resources Defense Council, Inc., 470
U. S. 116, 125 (1985), and Chevron U. S. A. Inc. v. Natural
Resources Defense Council, Inc., 467 U. S. 837, 842–845
(1984)), the Court held that “the Corps’ ecological judgment
about the relationship between waters and their adjacent
wetlands provides an adequate basis for a legal judgment
that adjacent wetlands may be defined as waters under the
Act,” 474 U. S., at 134. The Court reserved, however, the
question of the Corps’ authority to regulate wetlands other
than those adjacent to open waters. See id., at 131–132,
n. 8.
In SWANCC, the Court considered the validity of the
Corps’ jurisdiction over ponds and mudflats that were
isolated in the sense of being unconnected to other waters
covered by the Act. 531 U. S., at 171. The property at
issue was an abandoned sand and gravel pit mining opera
tion where “remnant excavation trenches” had “evolv[ed]
into a scattering of permanent and seasonal ponds.” Id.,
at 163. Asserting jurisdiction pursuant to a regulation
called the “Migratory Bird Rule,” the Corps argued that
these isolated ponds were “waters of the United States”
(and thus “navigable waters” under the Act) because they
were used as habitat by migratory birds. Id., at 164–165.
The Court rejected this theory. “It was the significant
nexus between wetlands and ‘navigable waters,’ ” the
Court held, “that informed our reading of the [Act] in
Riverside Bayview Homes.” Id., at 167. Because such a
nexus was lacking with respect to isolated ponds, the
Court held that the plain text of the statute did not permit
the Corps’ action. Id., at 172.
Riverside Bayview and SWANCC establish the frame
work for the inquiry in the cases now before the Court: Do
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KENNEDY, J., concurring in judgment

the Corps’ regulations, as applied to the wetlands in Cara-
bell and the three wetlands parcels in Rapanos, constitute
a reasonable interpretation of “navigable waters” as in
Riverside Bayview or an invalid construction as in
SWANCC? Taken together these cases establish that in
some instances, as exemplified by Riverside Bayview, the
connection between a nonnavigable water or wetland and
a navigable water may be so close, or potentially so close,
that the Corps may deem the water or wetland a “naviga
ble water” under the Act. In other instances, as exempli
fied by SWANCC, there may be little or no connection.
Absent a significant nexus, jurisdiction under the Act is
lacking. Because neither the plurality nor the dissent
addresses the nexus requirement, this separate opinion, in
my respectful view, is necessary.
A
The plurality’s opinion begins from a correct premise.
As the plurality points out, and as Riverside Bayview
holds, in enacting the Clean Water Act Congress intended
to regulate at least some waters that are not navigable in
the traditional sense. Ante, at 12; Riverside Bayview, 474
U. S., at 133; see also SWANCC, supra, at 167. This
conclusion is supported by “the evident breadth of con
gressional concern for protection of water quality and
aquatic ecosystems.” Riverside Bayview, supra, at 133; see
also Milwaukee v. Illinois, 451 U. S. 304, 318 (1981) (de
scribing the Act as “an all-encompassing program of water
pollution regulation”). It is further compelled by statutory
text, for the text is explicit in extending the coverage of the
Act to some nonnavigable waters. In a provision allowing
States to assume some regulatory functions of the Corps
(an option Michigan has exercised), the Act limits States
to issuing permits for:
“the discharge of dredged or fill material into the
navigable waters (other than those waters which are
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KENNEDY, J., concurring in judgment

presently used, or are susceptible to use in their natu
ral condition or by reasonable improvement as a
means to transport interstate or foreign commerce
shoreward to their ordinary high water mark, includ
ing all waters which are subject to the ebb and flow of
the tide shoreward to their ordinary high water mark,
or mean higher high water mark on the west coast,
including wetlands adjacent thereto) within its juris
diction.” 33 U. S. C. §1344(g)(1).
Were there no Clean Water Act “navigable waters” apart
from waters “presently used” or “susceptible to use” in inter
state commerce, the “other than” clause, which begins the
long parenthetical statement, would overtake the delegation
of authority the provision makes at the outset. Congress, it
follows, must have intended a broader meaning for navigable
waters. The mention of wetlands in the “other than” clause,
moreover, makes plain that at least some wetlands fall
within the scope of the term “navigable waters.” See River
side Bayview, supra, at 138–139, and n. 11.
From this reasonable beginning the plurality proceeds
to impose two limitations on the Act; but these limitations,
it is here submitted, are without support in the language
and purposes of the Act or in our cases interpreting it.
First, because the dictionary defines “waters” to mean
“water ‘[a]s found in streams and bodies forming geo
graphical features such as oceans, rivers, [and] lakes,’ or
‘the flowing or moving masses, as of waves or floods, mak
ing up such streams or bodies,” ante, at 13 (quoting Web
ster’s New International Dictionary 2882 (2d ed. 1954)
(hereinafter Webster’s Second)), the plurality would con
clude that the phrase “navigable waters” permits Corps
and EPA jurisdiction only over “relatively permanent,
standing or flowing bodies of water,” ante, at 13–14—a
category that in the plurality’s view includes “seasonal”
rivers, that is, rivers that carry water continuously except
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KENNEDY, J., concurring in judgment

during “dry months,” but not intermittent or ephemeral
streams, ante, at 13–15, and n. 5. Second, the plurality
asserts that wetlands fall within the Act only if they bear
“a continuous surface connection to bodies that are ‘waters
of the United States’ in their own right”—waters, that is,
that satisfy the plurality’s requirement of permanent
standing water or continuous flow. Ante, at 23–24.
The plurality’s first requirement—permanent standing
water or continuous flow, at least for a period of “some
months,” ante, at 13–14, and n. 5—makes little practical
sense in a statute concerned with downstream water
quality. The merest trickle, if continuous, would count as
a “water” subject to federal regulation, while torrents
thundering at irregular intervals through otherwise dry
channels would not. Though the plurality seems to pre
sume that such irregular flows are too insignificant to be
of concern in a statute focused on “waters,” that may not
always be true. Areas in the western parts of the Nation
provide some examples. The Los Angeles River, for in
stance, ordinarily carries only a trickle of water and often
looks more like a dry roadway than a river. See, e.g., B.
Gumprecht, The Los Angeles River: Its Life, Death, and
Possible Rebirth 1–2 (1999); Martinez, City of Angels’
Signature River Tapped for Rebirth, Chicago Tribune,
Apr. 10, 2005, section 1, p. 8. Yet it periodically releases
water-volumes so powerful and destructive that it has
been encased in concrete and steel over a length of some
50 miles. See Gumprecht, supra, at 227. Though this
particular waterway might satisfy the plurality’s test, it is
illustrative of what often-dry watercourses can become
when rain waters flow. See, e.g., County of Los Angeles
Dept. of Public Works, Water Resources Division:
2002–2003 Hydrologic Report, Runoff, Daily Discharge,
F377–R BOUQUET CANYON CREEK at Urbandale
Avenue 11107860 Bouquet Creek Near Saugus,
CA, http://ladpw.org/wrd/report/0203/runoff/discharge.cfm
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KENNEDY, J., concurring in judgment

(indicating creek carried no flow for much of the year but
carried 122 cubic feet per second on Feb. 12, 2003).
To be sure, Congress could draw a line to exclude irregu
lar waterways, but nothing in the statute suggests it has
done so. Quite the opposite, a full reading of the diction
ary definition precludes the plurality’s emphasis on per
manence: The term “waters” may mean “flood or inunda
tion,” Webster’s Second 2882, events that are
impermanent by definition. Thus, although of course the
Act’s use of the adjective “navigable” indicates a focus on
waterways rather than floods, Congress’ use of “waters”
instead of “water,” ante, at 13, does not necessarily carry
the connotation of “relatively permanent, standing or
flowing bodies of water,” ante, at 13–14. (And contrary to
the plurality’s suggestion, ante, at 13, n. 4, there is no
indication in the dictionary that the “flood or inundation”
definition is limited to poetry.) In any event, even grant
ing the plurality’s preferred definition—that “waters”
means “water ‘[a]s found in streams and bodies forming
geographical features such as oceans, rivers, [and] lakes,’ ”
ante, at 13 (quoting Webster’s Second 2882)—the dissent
is correct to observe that an intermittent flow can consti
tute a stream, in the sense of “ ‘a current or course of
water or other fluid, flowing on the earth,’ ” ante, at 14,
n. 6 (quoting Webster’s Second 2493), while it is flowing.
See post, at 15–16 (STEVENS, J., dissenting) (also noting
Court’s use of the phrase “ ‘intermittent stream’ ” in Harri
sonville v. W. S. Dickey Clay Mfg. Co., 289 U. S. 334, 335
(1933)). It follows that the Corps can reasonably interpret
the Act to cover the paths of such impermanent streams.
Apart from the dictionary, the plurality invokes River
side Bayview to support its interpretation that the term
“waters” is so confined, but this reliance is misplaced. To
be sure, the Court there compared wetlands to “rivers,
streams, and other hydrographic features more conven
tionally identifiable as ‘waters.’ ” 474 U. S., at 131. It is
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KENNEDY, J., concurring in judgment

quite a stretch to claim, however, that this mention of
hydrographic features “echoe[s]” the dictionary’s reference
to “ ‘geographical features such as oceans, rivers, [and]
lakes.’ ” Ante, at 16 (quoting Webster’s Second 2882). In
fact the Riverside Bayview opinion does not cite the dic
tionary definition on which the plurality relies, and the
phrase “hydrographic features” could just as well refer to
intermittent streams carrying substantial flow to naviga
ble waters. See Webster’s Second 1221 (defining “hydro
graphy” as “[t]he description and study of seas, lakes,
rivers, and other waters; specif[ically] . . . [t]he measure
ment of flow and investigation of the behavior of streams,
esp[ecially] with reference to the control or utilization of
their waters”).
Also incorrect is the plurality’s attempt to draw support
from the statutory definition of “point source” as “any
discernible, confined and discrete conveyance, including
but not limited to any pipe, ditch, channel, tunnel, con
duit, well, discrete fissure, container, rolling stock, concen
trated animal feeding operation, or vessel or other floating
craft, from which pollutants are or may be discharged.” 33
U. S. C. §1362(14). This definition is central to the Act’s
regulatory structure, for the term “discharge of a pollut
ant” is defined in relevant part to mean “any addition of
any pollutant to navigable waters from any point source,”
§1362(12). Interpreting the point-source definition, the
plurality presumes, first, that the point-source examples
describe “watercourses through which intermittent waters
typically flow,” and second, that point sources and naviga
ble waters are “separate and distinct categories.” Ante, at
17. From this the plurality concludes, by a sort of nega
tive inference, that navigable waters may not be intermit
tent. The conclusion is unsound. Nothing in the point-
source definition requires an intermittent flow. Polluted
water could flow night and day from a pipe, channel, or
conduit and yet still qualify as a point source; any con
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KENNEDY, J., concurring in judgment

trary conclusion would likely exclude, among other things,
effluent streams from sewage treatment plants. As a
result, even were the statute read to require continuity of
flow for navigable waters, certain water-bodies could
conceivably constitute both a point source and a water. At
any rate, as the dissent observes, the fact that point
sources may carry continuous flow undermines the plural
ity’s conclusion that covered “waters” under the Act may
not be discontinuous. See post, at 17.
The plurality’s second limitation—exclusion of wetlands
lacking a continuous surface connection to other jurisdic
tional waters—is also unpersuasive. To begin with, the
plurality is wrong to suggest that wetlands are “indistin
guishable” from waters to which they bear a surface con
nection. Ante, at 37. Even if the precise boundary may be
imprecise, a bog or swamp is different from a river. The
question is what circumstances permit a bog, swamp, or
other nonnavigable wetland to constitute a “navigable
water” under the Act—as §1344(g)(1), if nothing else,
indicates is sometimes possible, see supra, at 10–11.
Riverside Bayview addressed that question and its answer
is inconsistent with the plurality’s theory. There, in up
holding the Corps’ authority to regulate “wetlands adja
cent to other bodies of water over which the Corps has
jurisdiction,” the Court deemed it irrelevant whether “the
moisture creating the wetlands . . . find[s] its source in the
adjacent bodies of water.” 474 U. S., at 135. The Court
further observed that adjacency could serve as a valid
basis for regulation even as to “wetlands that are not
significantly intertwined with the ecosystem of adjacent
waterways.” Id., at 135, n. 9. “If it is reasonable,” the
Court explained, “for the Corps to conclude that in the
majority of cases, adjacent wetlands have significant
effects on water quality and the aquatic ecosystem, its
definition can stand.” Ibid.
The Court in Riverside Bayview did note, it is true, the
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KENNEDY, J., concurring in judgment

difficulty of defining where “water ends and land begins,”
id., at 132, and the Court cited that problem as one reason
for deferring to the Corps’ view that adjacent wetlands
could constitute waters. Given, however, the further
recognition in Riverside Bayview that an overinclusive
definition is permissible even when it reaches wetlands
holding moisture disconnected from adjacent water-bodies,
id., at 135, and n. 9, Riverside Bayview’s observations
about the difficulty of defining the water’s edge cannot be
taken to establish that when a clear boundary is evident,
wetlands beyond the boundary fall outside the Corps’
jurisdiction.
For the same reason Riverside Bayview also cannot be
read as rejecting only the proposition, accepted by the
Court of Appeals in that case, that wetlands covered by
the Act must contain moisture originating in neighboring
waterways. See id., at 125, 134. Since the Court of Ap
peals had accepted that theory, the Court naturally ad
dressed it. Yet to view the decision’s reasoning as limited
to that issue—an interpretation the plurality urges here,
ante, at 33, n. 13—would again overlook the opinion’s
broader focus on wetlands’ “significant effects on water
quality and the aquatic ecosystem,” 474 U. S., at 135, n. 9.
In any event, even were this reading of Riverside Bayview
correct, it would offer no support for the plurality’s pro
posed requirement of a “continuous surface connection,”
ante, at 23. The Court in Riverside Bayview rejected the
proposition that origination in flooding was necessary for
jurisdiction over wetlands. It did not suggest that a flood-
based origin would not support jurisdiction; indeed, it
presumed the opposite. See 474 U. S., at 134 (noting that
the Corps’ view was valid “even for wetlands that are not
the result of flooding or permeation” (emphasis added)).
Needless to say, a continuous connection is not necessary
for moisture in wetlands to result from flooding—the
connection might well exist only during floods.
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KENNEDY, J., concurring in judgment

SWANCC, likewise, does not support the plurality’s
surface-connection requirement. SWANCC’s holding that
“nonnavigable, isolated, intrastate waters,” 531 U. S., at 171,
are not “navigable waters” is not an explicit or implicit
overruling of Riverside Bayview’s approval of adjacency as
a factor in determining the Corps’ jurisdiction. In reject
ing the Corps’ claimed authority over the isolated ponds in
SWANCC, the Court distinguished adjacent nonnavigable
waters such as the wetlands addressed in Riverside Bay-
view. 531 U. S., at 167, 170–171.
As Riverside Bayview recognizes, the Corps’ adjacency
standard is reasonable in some of its applications. Indeed,
the Corps’ view draws support from the structure of the
Act, while the plurality’s surface-water-connection re
quirement does not.
As discussed above, the Act’s prohibition on the dis
charge of pollutants into navigable waters, 33 U. S. C.
§1311(a), covers both the discharge of toxic materials such
as sewage, chemical waste, biological material, and radio
active material and the discharge of dredged spoil, rock,
sand, cellar dirt, and the like. All these substances are
defined as pollutants whose discharge into navigable
waters violates the Act. §§1311(a), 1362(6), (12). One
reason for the parallel treatment may be that the dis
charge of fill material can impair downstream water qual
ity. The plurality argues otherwise, asserting that
dredged or fill material “does not normally wash down
stream.” Ante, at 26. As the dissent points out, this
proposition seems questionable as an empirical matter.
See post, at 22. It seems plausible that new or loose fill,
not anchored by grass or roots from other vegetation, could
travel downstream through waterways adjacent to a wet
land; at the least this is a factual possibility that the
Corps’ experts can better assess than can the plurality.
Silt, whether from natural or human sources, is a major
factor in aquatic environments, and it may clog water
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KENNEDY, J., concurring in judgment

ways, alter ecosystems, and limit the useful life of dams.
See, e.g., Fountain, Unloved, But Not Unbuilt, N. Y.
Times, June 5, 2005 section 4, p. 3, col. 1; DePalma, Dam
to Be Demolished to Save an Endangered Species, N. Y.
Times, Apr. 26, 2004, section B, p. 1, col. 2; MacDougall,
Damage Can Be Irreversible, Los Angeles Times, June 19,
1987, pt. 1, p. 10, col. 4.
Even granting, however, the plurality’s assumption that
fill material will stay put, Congress’ parallel treatment of
fill material and toxic pollution may serve another pur
pose. As the Court noted in Riverside Bayview, “the Corps
has concluded that wetlands may serve to filter and purify
water draining into adjacent bodies of water, 33 CFR
§320.4(b)(2)(vii) (1985), and to slow the flow of surface
runoff into lakes, rivers, and streams and thus prevent
flooding and erosion, see §§320.4(b)(2)(iv) and (v).” 474
U. S., at 134. Where wetlands perform these filtering and
runoff-control functions, filling them may increase down
stream pollution, much as a discharge of toxic pollutants
would. Not only will dirty water no longer be stored and
filtered but also the act of filling and draining itself may
cause the release of nutrients, toxins, and pathogens that
were trapped, neutralized, and perhaps amenable to filter
ing or detoxification in the wetlands. See U. S. Congress,
Office of Technology Assessment, Wetlands: Their Use
and Regulation, OTA–O–206 pp. 43, 48–52 (Mar. 1984),
http://govinfo.library.unt.edu/ota/OTA_4/DATA/1984/8433
.pdf (hereinafter OTA). In many cases, moreover, filling in
wetlands separated from another water by a berm can
mean that flood water, 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.
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KENNEDY, J., concurring in judgment

In sum the plurality’s opinion is inconsistent with the
Act’s text, structure, and purpose. As a fallback the plu
rality suggests that avoidance canons would compel its
reading even if the text were unclear. Ante, at 18–20. In
SWANCC, as one reason for rejecting the Corps’ assertion
of jurisdiction over the isolated ponds at issue there, the
Court observed that this “application of [the Corps’] regu
lations” would raise significant questions of Commerce
Clause authority and encroach on traditional state land-
use regulation. 531 U. S., at 174. As SWANCC observed,
ibid., and as the plurality points out here, ante, at 18, the
Act states that “[i]t is the policy of the Congress to recog
nize, preserve, and protect the primary responsibilities and
rights of States to prevent, reduce, and eliminate pollution,
[and] to plan the development and use . . . of land and water
resources,” 33 U. S. C. §1251(b). The Court in SWANCC
cited this provision as evidence that a clear statement sup
porting jurisdiction in applications raising constitutional
and federalism difficulties was lacking. 531 U. S., at 174.
The concerns addressed in SWANCC do not support the
plurality’s interpretation of the Act. In SWANCC, by inter
preting the Act to require a significant nexus with naviga
ble waters, the Court avoided applications—those involv
ing waters without a significant nexus—that appeared
likely, as a category, to raise constitutional difficulties and
federalism concerns. Here, in contrast, the plurality’s
interpretation does not fit the avoidance concerns it raises.
On the one hand, when a surface-water connection is
lacking, the plurality forecloses jurisdiction over wetlands
that abut navigable-in-fact waters—even though such
navigable waters were traditionally subject to federal
authority. On the other hand, by saying the Act covers
wetlands (however remote) possessing a surface-water
connection with a continuously flowing stream (however
small), the plurality’s reading would permit applications of
the statute as far from traditional federal authority as are
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KENNEDY, J., concurring in judgment

the waters it deems beyond the statute’s reach. Even
assuming, then, that federal regulation of remote wet
lands and nonnavigable waterways would raise a difficult
Comerce Clause issue notwithstanding those waters’
aggregate effects on national water quality, but cf.
Wickard v. Filburn, 317 U. S. 111 (1942); see also infra, at
25–26, the plurality’s reading is not responsive to this
concern. As for States’ “responsibilities and rights,”
§1251(b), it is noteworthy that 33 States plus the District of
Columbia have filed an amici brief in this litigation assert
ing that the Clean Water Act is important to their own
water policies. See Brief for States of New York et al. 1–3.
These amici note, among other things, that the Act protects
downstream States from out-of-state pollution that they
cannot themselves regulate. Ibid.
It bears mention also that the plurality’s overall tone
and approach—from the characterization of acres of wet
lands destruction as “backfilling . . . wet fields,” ante, at 2,
to the rejection of Corps authority over “man-made drain
age ditches” and “dry arroyos” without regard to how
much water they periodically carry, ante, at 15, to the
suggestion, seemingly contrary to Congress’ judgment,
that discharge of fill material is inconsequential for adja
cent waterways, ante, at 26, and n. 11—seems unduly
dismissive of the interests asserted by the United States
in these cases. Important public interests are served by
the Clean Water Act in general and by the protection of
wetlands in particular. To give just one example, amici
here have noted that nutrient-rich runoff from the Missis
sippi River has created a hypoxic, or oxygen-depleted,
“dead zone” in the Gulf of Mexico that at times approaches
the size of Massachusetts and New Jersey. Brief for Asso
ciation of State Wetland Managers et al. 21–23; Brief for
Environmental Law Institute 23. Scientific evidence
indicates that wetlands play a critical role in controlling
and filtering runoff. See, e.g., OTA 43, 48–52; R. Tiner, In
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KENNEDY, J., concurring in judgment

Search of Swampland: A Wetland Sourcebook and Field
Guide 93–95 (2d ed. 2005); Whitmire & Hamilton, Rapid
Removal of Nitrate and Sulfate in Freshwater Wetland
Sediments, 34 J. Env. Quality 2062 (2005). It is true, as
the plurality indicates, that environmental concerns pro
vide no reason to disregard limits in the statutory text,
ante, at 27, but in my view the plurality’s opinion is not a
correct reading of the text. The limits the plurality would
impose, moreover, give insufficient deference to Congress’
purposes in enacting the Clean Water Act and to the
authority of the Executive to implement that statutory
mandate.
Finally, it should go without saying that because the
plurality presents its interpretation of the Act as the only
permissible reading of the plain text, ante, at 20, 23–24,
the Corps would lack discretion, under the plurality’s
theory, to adopt contrary regulations. THE CHIEF JUSTICE
suggests that if the Corps and EPA had issued new regu
lations after SWANCC they would have “enjoyed plenty of
room to operate in developing some notion of an outer
bound to the reach of their authority” and thus could have
avoided litigation of the issues we address today. Ante, at
2. That would not necessarily be true under the opinion
THE CHIEF JUSTICE has joined. New rulemaking could
have averted the disagreement here only if the Corps had
anticipated the unprecedented reading of the Act that the
plurality advances.
B
While the plurality reads nonexistent requirements into
the Act, the dissent reads a central requirement out—
namely, the requirement that the word “navigable” in
“navigable waters” be given some importance. Although
the Court has held that the statute’s language invokes
Congress’ traditional authority over waters navigable in
fact or susceptible of being made so, SWANCC, 531 U. S.,
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KENNEDY, J., concurring in judgment

at 172 (citing Appalachian Power, 311 U. S., at 407–408),
the dissent would permit federal regulation whenever
wetlands lie alongside a ditch or drain, however remote
and insubstantial, that eventually may flow into tradi
tional navigable waters. The deference owed to the Corps’
interpretation of the statute does not extend so far.
Congress’ choice of words creates difficulties, for the Act
contemplates regulation of certain “navigable waters” that
are not in fact navigable. Supra, at 10–11. Nevertheless,
the word “navigable” in the Act must be given some effect.
See SWANCC, supra, at 172. Thus, in SWANCC the
Court rejected the Corps’ assertion of jurisdiction over
isolated ponds and mudflats bearing no evident connection
to navigable-in-fact waters. And in Riverside Bayview,
while the Court indicated that “the term ‘navigable’ as
used in the Act is of limited import,” 474 U. S., at 133, it
relied, in upholding jurisdiction, on the Corps’ judgment
that “wetlands adjacent to lakes, rivers, streams, and
other bodies of water may function as integral parts of the
aquatic environment even when the moisture creating the
wetlands does not find its source in the adjacent bodies of
water,” id., at 135. The implication, of course, was that
wetlands’ status as “integral parts of the aquatic environ
ment”—that is, their significant nexus with navigable
waters—was what established the Corps’ jurisdiction over
them as waters of the United States.
Consistent with SWANCC and Riverside Bayview and
with the need to give the term “navigable” some meaning,
the Corps’ jurisdiction over wetlands depends upon the
existence of a significant nexus between the wetlands in
question and navigable waters in the traditional sense.
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 biologi
cal integrity of the Nation’s waters,” 33 U. S. C. §1251(a),
and it pursued that objective by restricting dumping and
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KENNEDY, J., concurring in judgment

filling in “navigable waters,” §§1311(a), 1362(12). With
respect to wetlands, the rationale for Clean Water Act
regulation is, as the Corps has recognized, that wetlands
can perform critical functions related to the integrity of
other waters—functions such as pollutant trapping, flood
control, and runoff storage. 33 CFR §320.4(b)(2). Accord
ingly, wetlands possess the requisite nexus, and thus come
within the statutory phrase “navigable waters,” if the
wetlands, either alone or in combination with similarly
situated lands in the region, significantly affect the chemi
cal, physical, and biological integrity of other covered
waters more readily understood as “navigable.” When, in
contrast, wetlands’ effects on water quality are speculative
or insubstantial, they fall outside the zone fairly encom
passed by the statutory term “navigable waters.”
Although the dissent acknowledges that wetlands’ eco
logical functions vis-à-vis other covered waters are the
basis for the Corps’ regulation of them, post, at 10–11, it
concludes that the ambiguity in the phrase “navigable
waters” allows the Corps to construe the statute as reach
ing all “non-isolated wetlands,” just as it construed the Act
to reach the wetlands adjacent to navigable-in-fact waters
in Riverside Bayview, see post, at 11. This, though, seems
incorrect. The Corps’ theory of jurisdiction in these con
solidated cases—adjacency to tributaries, however remote
and insubstantial—raises concerns that go beyond the
holding of Riverside Bayview; and so the Corps’ assertion
of jurisdiction cannot rest on that case.
As applied to wetlands adjacent to navigable-in-fact
waters, the Corps’ conclusive standard for jurisdiction
rests upon a reasonable inference of ecologic interconnec
tion, and the assertion of jurisdiction for those wetlands is
sustainable under the Act by showing adjacency alone.
That is the holding of Riverside Bayview. Furthermore,
although the Riverside Bayview Court reserved the ques
tion of the Corps’ authority over “wetlands that are not
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KENNEDY, J., concurring in judgment

adjacent to bodies of open water,” 474 U. S., at 131–132,
n. 8, and in any event addressed no factual situation other
than wetlands adjacent to navigable-in-fact waters, it may
well be the case that Riverside Bayview’s reasoning—
supporting jurisdiction without any inquiry beyond adja
cency—could apply equally to wetlands adjacent to certain
major tributaries. Through regulations or adjudication,
the Corps may choose to identify categories of tributaries
that, due to their volume of flow (either annually or on
average), their proximity to navigable waters, or other
relevant considerations, are significant enough that wet
lands adjacent to them are likely, in the majority of cases,
to perform important functions for an aquatic system
incorporating navigable waters.
The Corps’ existing standard for tributaries, however,
provides no such assurance. As noted earlier, the Corps
deems a water a tributary if it feeds into a traditional
navigable water (or a tributary thereof) and possesses an
ordinary high-water mark, defined as a “line on the shore
established by the fluctuations of water and indicated by
[certain] physical characteristics,” §328.3(e). See supra, at
3. This standard presumably provides a rough measure
of the volume and regularity of flow. Assuming it is
subject to reasonably consistent application, but see U. S.
General Accounting Office, Report to the Chairman,
Subcommittee on Energy Policy, Natural Resources and
Regulating Affairs, Committee on Reform, House of
Representatives, Waters and Wetlands: Corps of Engi
neers Needs to Evaluate Its District Office Practices in
Determining Jurisdiction, GAO–04–297 pp. 3–4 (Feb.
2004), http://www.gao.gov/new.items/d04297.pdf (noting
variation in results among Corps district offices), it may
well provide a reasonable measure of whether specific
minor tributaries bear a sufficient nexus with other regu
lated waters to constitute “navigable waters” under the
Act. Yet the breadth of this standard—which seems to
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KENNEDY, J., concurring in judgment

leave wide room for regulation of drains, ditches, and
streams remote from any navigable-in-fact water and
carrying only minor water-volumes towards it—precludes
its adoption as the determinative measure of whether
adjacent wetlands are likely to play an important role in
the integrity of an aquatic system comprising navigable
waters as traditionally understood. Indeed, in many cases
wetlands adjacent to tributaries covered by this standard
might appear little more related to navigable-in-fact wa
ters than were the isolated ponds held to fall beyond the
Act’s scope in SWANCC. Cf. Leibowitz & Nadeau, Isolated
Wetlands: State-of-the-Science and Future Directions, 23
Wetlands 663, 669 (2003) (noting that “ ‘isolated’ is gener
ally a matter of degree”).
When the Corps seeks to regulate wetlands adjacent to
navigable-in-fact waters, it may rely on adjacency to estab
lish its jurisdiction. Absent more specific regulations,
however, the Corps must establish a significant nexus on a
case-by-case basis when it seeks to regulate wetlands
based on adjacency to nonnavigable tributaries. Given the
potential overbreadth of the Corps’ regulations, this show
ing is necessary to avoid unreasonable applications of the
statute. Where an adequate nexus is established for a
particular wetland, it may be permissible, as a matter of
administrative convenience or necessity, to presume cov
ered status for other comparable wetlands in the region.
That issue, however, is neither raised by these facts nor
addressed by any agency regulation that accommodates
the nexus requirement outlined here.
This interpretation of the Act does not raise federalism
or Commerce Clause concerns sufficient to support a
presumption against its adoption. To be sure, the signifi
cant nexus requirement may not align perfectly with the
traditional extent of federal authority. Yet in most cases
regulation of wetlands that are adjacent to tributaries and
possess a significant nexus with navigable waters will
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KENNEDY, J., concurring in judgment

raise no serious constitutional or federalism difficulty. Cf.
Pierce County v. Guillen, 537 U. S. 129, 147 (2003) (up
holding federal legislation “aimed at improving safety in
the channels of commerce”); Oklahoma ex rel. Phillips v.
Guy F. Atkinson Co., 313 U. S. 508, 524–525 (1941)
(“[J]ust as control over the non-navigable parts of a river
may be essential or desirable in the interests of the navi
gable portions, so may the key to flood control on a navi
gable stream be found in whole or in part in flood control
on its tributaries . . . . [T]he exercise of the granted power
of Congress to regulate interstate commerce may be aided
by appropriate and needful control of activities and agen
cies which, though intrastate, affect that commerce”). As
explained earlier, moreover, and as exemplified by
SWANCC, the significant-nexus test itself prevents prob
lematic applications of the statute. See supra, at 19–20;
531 U. S., at 174. The possibility of legitimate Commerce
Clause and federalism concerns in some circumstances
does not require the adoption of an interpretation that
departs in all cases from the Act’s text and structure. See
Gonzales v. Raich, 545 U. S. 1, __ (2005) (slip op., at 14)
(“[W]hen a general regulatory statute bears a substantial
relation to commerce, the de minimis character of individ
ual instances arising under that statute is of no conse
quence” (internal quotation marks omitted)).
III
In both the consolidated cases before the Court the
record contains evidence suggesting the possible existence
of a significant nexus according to the principles outlined
above. Thus the end result in these cases and many oth
ers to be considered by the Corps may be the same as that
suggested by the dissent, namely, that the Corps’ asser
tion of jurisdiction is valid. Given, however, that neither
the agency nor the reviewing courts properly considered
the issue, a remand is appropriate, in my view, for appli
 Cite as: 547 U. S. ____ (2006) 27

KENNEDY, J., concurring in judgment

cation of the controlling legal standard.
Rapanos
As the dissent points out, in Rapanos, No. 04–1034, an
expert whom the District Court found “eminently quali
fied” and “highly credible,” App. to Pet. for Cert. B7, testi
fied that the wetlands were providing “habitat, sediment
trapping, nutrient recycling, and flood peak diminution,
reduction flow water augmentation.” 4 Tr. 96 (Apr. 5,
1999). Although the expert had “not studied the upstream
drainage of these sites” and thus could not assert that the
wetlands were performing important pollutant-trapping
functions, ibid., he did observe:
“we have a situation in which the flood water attenua
tion in that water is held on the site in the wetland
. . . such that it does not add to flood peak. By the
same token it would have some additional water flow
ing into the rivers during the drier periods, thus, in
creasing the low water flow. . . . By the same token on
all of the sites to the extent that they slow the flow of
water off of the site they will also accumulate sedi
ment and thus trap sediment and hold nutrients for
use in those wetlands systems later in the season as
well.” Id., at 95–96.
In addition, in assessing the hydrology prong of the three-
part wetlands test, see supra, at 3–4, the District Court
made extensive findings regarding water tables and
drainage on the parcels at issue. In applying the Corps’
jurisdictional regulations, the District Court found that
each of the wetlands bore surface water connections to
tributaries of navigable-in-fact waters.
Much the same evidence should permit the establish
ment of a significant nexus with navigable-in-fact waters,
particularly if supplemented by further evidence about the
significance of the tributaries to which the wetlands are
28 RAPANOS v. UNITED STATES

KENNEDY, J., concurring in judgment

connected. The Court of Appeals, however, though recog
nizing that under SWANCC such a nexus was required for
jurisdiction, held that a significant nexus “can be satisfied
by the presence of a hydrologic connection.” 376 F. 3d, at
639. Absent some measure of the significance of the con
nection for downstream water quality, this standard was
too uncertain. Under the analysis described earlier,
supra, at 22–23, 25, mere hydrologic connection should not
suffice in all cases; the connection may be too insubstan
tial for the hydrologic linkage to establish the required
nexus with navigable waters as traditionally understood.
In my view this case should be remanded so that the
District Court may reconsider the evidence in light of the
appropriate standard. See, e.g., Pullman-Standard v.
Swint, 456 U. S. 273, 291 (1982) (“When an appellate court
discerns that a district court has failed to make a finding
because of an erroneous view of the law, the usual rule is
that there should be a remand for further proceedings to
permit the trial court to make the missing findings”).
Carabell
In Carabell, No. 04–1384, the record also contains evi
dence bearing on the jurisdictional inquiry. The Corps
noted in deciding the administrative appeal that “[b]esides
the effects on wildlife habitat and water quality, the [dis
trict office] also noted that the project would have a major,
long-term detrimental effect on wetlands, flood retention,
recreation and conservation and overall ecology,” App.
218a. Similarly, in the district office’s permit evaluation,
Corps officers observed:
“The proposed work would destroy/adversely impact
an area that retains rainfall and forest nutrients and
would replace it with a new source area for runoff pol
lutants. Pollutants from this area may include lawn
fertilizers, herbicides, pesticides, road salt, oil, and
grease. These pollutants would then runoff directly
 Cite as: 547 U. S. ____ (2006) 29

KENNEDY, J., concurring in judgment

into the waterway. . . . Overall, the operation and use
of the proposed activity would have a major, long
term, negative impact on water quality. The cumula
tive impacts of numerous such projects would be ma
jor and negative as the few remaining wetlands in the
area are developed.” Id., at 97a–98a.
The Corps’ evaluation further noted that by “eliminat[ing]
the potential ability of the wetland to act as a sediment
catch basin,” the proposed project “would contribute to
increased runoff and accretion . . . along the drain and
further downstream in Auvase Creek.” Id., at 98a. And it
observed that increased runoff from the site would likely
cause downstream areas to “see an increase in possible
flooding magnitude and frequency.” Id., at 99a.
The conditional language in these assessments—“potential
ability,” “possible flooding”—could suggest an undue degree
of speculation, and a reviewing court must identify sub
stantial evidence supporting the Corps’ claims, see 5
U. S. C. §706(2)(E). Nevertheless, the record does show
that factors relevant to the jurisdictional inquiry have
already been noted and considered. As in Rapanos,
though, the record gives little indication of the quantity
and regularity of flow in the adjacent tributaries—a con
sideration that may be important in assessing the nexus.
Also, as in Rapanos, the legal standard applied to the facts
was imprecise.
The Court of Appeals, considering the Carabell case
after its Rapanos decision, framed the inquiry in terms of
whether hydrologic connection is required to establish a
significant nexus. The court held that it is not, and that
much of its holding is correct. Given the role wetlands
play in pollutant filtering, flood control, and runoff stor
age, it may well be the absence of hydrologic connection (in
the sense of interchange of waters) that shows the wet
lands’ significance for the aquatic system. In the adminis
30 RAPANOS v. UNITED STATES

KENNEDY, J., concurring in judgment

trative decision under review, however, the Corps based
its jurisdiction solely on the wetlands’ adjacency to the
ditch opposite the berm on the property’s edge. As ex
plained earlier, mere adjacency to a tributary of this sort
is insufficient; a similar ditch could just as well be located
many miles from any navigable-in-fact water and carry
only insubstantial flow towards it. A more specific in
quiry, based on the significant nexus standard, is there
fore necessary. Thus, a remand is again required to per
mit application of the appropriate legal standard. See,
e.g., INS v. Orlando Ventura, 537 U. S. 12, 16 (2002) (per
curiam) (“Generally speaking, a court of appeals should
remand a case to an agency for decision of a matter that
statutes place primarily in agency hands”).
* * *
In these consolidated cases I would vacate the judgments
of the Court of Appeals and remand for consideration
whether the specific wetlands at issue possess a signifi
cant nexus with navigable waters.
 Cite as: 547 U. S. ____ (2006) 1

STEVENS, J., dissenting

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 04–1034 and 04–1384
_________________

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS
04–1034 v.
UNITED STATES

JUNE CARABELL ET AL., PETITIONERS
04–1384 v.
UNITED STATES ARMY CORPS OF ENGINEERS ET AL.
ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE SIXTH CIRCUIT
[June 19, 2006]

JUSTICE STEVENS, with whom JUSTICE SOUTER, JUSTICE
GINSBURG, and JUSTICE BREYER join, dissenting.
In 1972, Congress decided to “restore and maintain the
chemical, physical, and biological integrity of the Nation’s
waters” by passing what we now call the Clean Water Act.
86 Stat. 816, as amended, 33 U. S. C. §1251 et seq. The
costs of achieving the Herculean goal of ending water
pollution by 1985, see §1251(a), persuaded President
Nixon to veto its enactment, but both Houses of Congress
voted to override that veto by overwhelming margins. To
achieve its goal, Congress prohibited “the discharge of any
pollutant”—defined to include “any addition of any pollut
ant to navigable waters from any point source”—without a
permit issued by the Army Corps of Engineers (Army
Corps or Corps) or the Environmental Protection Agency
(EPA). §§1311(a), 1362(12)(A). Congress further defined
“navigable waters” to mean “the waters of the United
States.” §1362(7).
The narrow question presented in No. 04–1034 is
2 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

whether wetlands adjacent to tributaries of traditionally
navigable waters are “waters of the United States” subject
to the jurisdiction of the Army Corps; the question in No.
04–1384 is whether a manmade berm separating a wet
land from the adjacent tributary makes a difference. The
broader question is whether regulations that have pro
tected the quality of our waters for decades, that were
implicitly approved by Congress, and that have been
repeatedly enforced in case after case, must now be re
vised in light of the creative criticisms voiced by the plu
rality and JUSTICE KENNEDY today. Rejecting more than
30 years of practice by the Army Corps, the plurality
disregards the nature of the congressional delegation to
the agency and the technical and complex character of the
issues at stake. JUSTICE KENNEDY similarly fails to defer
sufficiently to the Corps, though his approach is far more
faithful to our precedents and to principles of statutory
interpretation than is the plurality’s.
In my view, the proper analysis is straightforward. The
Army Corps has determined that wetlands adjacent to
tributaries of traditionally navigable waters preserve the
quality of our Nation’s waters by, among other things,
providing habitat for aquatic animals, keeping excessive
sediment and toxic pollutants out of adjacent waters, and
reducing downstream flooding by absorbing water at times
of high flow. The Corps’ resulting decision to treat these
wetlands as encompassed within the term “waters of the
United States” is a quintessential example of the Execu
tive’s reasonable interpretation of a statutory provision.
See Chevron U. S. A. Inc. v. Natural Resources Defense
Council, Inc., 467 U. S. 837, 842–845 (1984).
Our unanimous decision in United States v. Riverside
Bayview Homes, Inc., 474 U. S. 121 (1985), was faithful to
our duty to respect the work product of the Legislative and
Executive Branches of our Government. Today’s judicial
amendment of the Clean Water Act is not.
 Cite as: 547 U. S. ____ (2006) 3

STEVENS, J., dissenting

I
At each of the three sites at issue in No. 04–1034, the
petitioners filled large areas of wetlands without permits,
despite being on full notice of the Corps’ regulatory re
quirements. Because the plurality gives short shrift to the
facts of this case—as well as to those of No. 04–1384—I
shall discuss them at some length.
The facts related to the 230-acre Salzburg site are illus
trative. In 1988, John Rapanos asked the Michigan De
partment of Natural Resources (MDNR) to inspect the site
“in order to discuss with him the feasibility of building a
shopping center there.” App. to Pet. for Cert. in No. 04–
1034, p. B15. An MDNR inspector informed Rapanos that
the land probably included wetlands that were “waters of
the United States” and sent him an application for a per
mit under §404 of the Act.1 Rapanos then hired a wetland
consultant, Dr. Frederick Goff. After Dr. Goff concluded
that the land did in fact contain many acres of wetlands,
“Rapanos threatened to ‘destroy’ Dr. Goff if he did not
destroy the wetland report, and refused to pay Dr. Goff
unless and until he complied.” Ibid. In the meantime,
without applying for a permit, Rapanos hired construction
companies to do $350,000 worth of work clearing the land,
filling in low spots, and draining subsurface water. After
Rapanos prevented MDNR inspectors from visiting the
site, ignored an MDNR cease-and-desist letter, and re
fused to obey an administrative compliance order issued
by the EPA, the matter was referred to the Department of
Justice. In the civil case now before us, the District Court
found that Rapanos unlawfully filled 22 acres of wetlands.
Rapanos and his wife engaged in similar behavior at the
Hines Road and Pine River sites. Without applying for
§404 permits, they hired construction companies to per
——————
1 Pursuant to 33 U. S. C. §§1344(g)–(h), Michigan operates its own

§404 permitting program, subject to supervision from the Army Corps.
4 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

form extensive clearing and filling activities. They con
tinued these activities even after receiving EPA adminis
trative compliance orders directing them to cease the work
immediately. They ultimately spent $158,000 at the 275
acre Hines Road site, filling 17 of its existing 64 acres of
wetlands. At the 200-acre Pine River site, they spent
$463,000 and filled 15 of its 49 acres of wetlands.
Prior to their destruction, the wetlands at all three sites
had surface connections to tributaries of traditionally
navigable waters. The Salzburg wetlands connected to a
drain that flows into a creek that flows into the navigable
Kawkawlin River. The Hines Road wetlands connected to
a drain that flows into the navigable Tittabawassee River.
And the Pine River wetlands connected with the Pine
River, which flows into Lake Huron.
At trial, the Government put on a wetland expert, Dr.
Daniel Willard, whom the trial court found “eminently
qualified” and “highly credible.” Id., at B7. Dr. Willard
testified that the wetlands at these three sites provided
ecological functions in terms of “habitat, sediment trap
ping, nutrient recycling, and flood peak diminution.” 4 Tr.
96 (Apr. 5, 1999).2 He explained:
“[G]enerally for all of the . . . sites we have a situation
in which the flood water attenuation in that water is
held on the site in the wetland . . . such that it does
not add to flood peak. By the same token it would
have some additional water flowing into the rivers
during the drier periods, thus, increasing low water
flow.
. . . . .
“By the same token on all of the sites to the extent

——————
2 Dr. Willard did not “stud[y] the upstream drainage of these sites . . .

well enough to make a statement” about whether they also performed
pollutant-trapping functions. 4 Tr. 96.
 Cite as: 547 U. S. ____ (2006) 5

STEVENS, J., dissenting

that they slow the flow of water of the site they will
also accumulate sediment and thus trap sediment and
hold nutrients for use in those wetland systems later
in the season as well.” Id., at 95–96.
The District Court found that the wetlands at all three
sites were covered by the Clean Water Act and that the
Rapanoses had violated the Act by destroying them with
out permits. The Sixth Circuit unanimously affirmed.
376 F. 3d 629 (2004).
The facts of No. 04–1384 are less dramatic. The peti
tioners in that case own a 20-acre tract of land, of which
16 acres are wetlands, located in Macomb County a mile
from Lake St. Clair. These wetlands border a ditch that
flows into a drain that flows into a creek that flows into
Lake St. Clair. A 4-foot-wide manmade berm separates
the wetlands from the ditch; thus water rarely if ever
passes from wetlands to ditch or vice versa.
Petitioners applied for a permit to fill most of these
wetlands with 57,500 cubic yards of material. They in
tended to build a 112-unit condominium development on
the site. After inspecting the site and considering com
ments from, among others, the Water Quality Unit of the
Macomb County Prosecutor’s Office (which urged the
Corps to deny the permit because “[t]he loss of this high
quality wetland area would have an unacceptable adverse
effect on wildlife, water quality, and conservation of wet
lands resources,” App. in No. 04–1384, p. 79a), the Corps
denied the permit. Id., at 84a–126a. As summarized in a
letter sent to petitioners, reasons for denial included:
“Your parcel is primarily a forested wetland that pro
vides valuable seasonal habitat for aquatic organisms
and year round habitat for terrestrial organisms. Ad
ditionally, the site provides water storage functions
that, if destroyed, could result in an increased risk of
erosion and degradation of water quality in the Suth
6 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

erland-Oemig Drain, Auvase Creek, and Lake St.
Clair. The minimization of impacts to these wetlands
is important for conservation and the overall ecology
of the region. Because the project development area is
a forested wetland, the proposed project would destroy
the resources in such a manner that they would not
soon recover from impacts of the discharges. The ex
tent of impacts in the project area when considered
both individually and cumulatively would be unac
ceptable and contrary to the public interest.” Id., at
127a–128a.
As in No. 04–1034, the unanimous judgment of the Dis
trict and Circuit Judges was that the Corps has jurisdic
tion over this wetland because it is adjacent to a tributary
of traditionally navigable waters. 391 F. 3d 704 (CA6
2004). The Solicitor General defends both judgments.
II
Our unanimous opinion in Riverside Bayview squarely
controls these cases. There, we evaluated the validity of
the very same regulations at issue today. These regula
tions interpret “waters of the United States” to cover all
traditionally navigable waters; tributaries of these waters;
and wetlands adjacent to traditionally navigable waters or
their tributaries. 33 CFR §§328.3(a)(1), (5), and (7) (2005);
§§323.2(a)(1), (5), and (7) (1985). Although the particular
wetland at issue in Riverside Bayview abutted a navigable
creek, we framed the question presented as whether the
Clean Water Act “authorizes the Corps to require land
owners to obtain permits from the Corps before discharg
ing fill material into wetlands adjacent to navigable bodies
of water and their tributaries.” 474 U. S., at 123 (empha
sis added).3
——————
3 By contrast, we “d[id] not express any opinion” on the Corps’ addi

tional assertion of jurisdiction over “wetlands that are not adjacent to
 Cite as: 547 U. S. ____ (2006) 7

STEVENS, J., dissenting

We held that, pursuant to our decision in Chevron,
“our review is limited to the question whether it is
reasonable, in light of the language, policies, and leg
islative history of the Act for the Corps to exercise ju
risdiction over wetlands adjacent to but not regularly
flooded by rivers, streams, and other hydrographic
features more conventionally identifiable as ‘waters.’ ”
474 U. S., at 131.
Applying this standard, we held that the Corps’ decision
to interpret “waters of the United States” as encompassing
such wetlands was permissible. We recognized the practi
cal difficulties in drawing clean lines between land and
water, id., at 132, and deferred to the Corps’ judgment
that treating adjacent wetlands as “waters” would advance
the “congressional concern for protection of water quality
and aquatic ecosystems,” id., at 133.
——————
bodies of open water, see 33 CFR §323.2(a)(2) and (3) (1985).” 474 U. S.,
at 131–132, n. 8; see also id., at 124, n. 2 (making the same reserva
tion). Contrary to JUSTICE KENNEDY’s reading, ante, at 23–24 (opinion
concurring in judgment), we were not reserving the issue of the Corps’
jurisdiction over wetlands adjacent to tributaries, but only reserving
the issue of the Corps’ jurisdiction over truly isolated waters. A glance
at the cited regulation makes this clear. Section 323.2(a)(2) refers to
“[a]ll interstate waters including interstate wetlands” and §323.2(a)(3)
covers “[a]ll other waters such as intrastate lakes, rivers, streams
(including intermittent streams), mudflats, sandflats, wetlands,
sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds,
the use, degradation or destruction of which could affect interstate or
foreign commerce including any such waters.” See also Solid Waste
Agency of Northern Cook Cty. v. Army Corps of Engineers, 531 U. S. 159,
163–164 (2001) (considering the validity of an application of §328.3(a)(3)
(1999), which is substantively identical to §323.2(a)(3) (1985) and to
§323.2(a)(5) (1978)). Wetlands adjacent to tributaries of traditionally
navigable waters were covered in the 1985 regulation by other provi
sions of the regulation, namely a combination of §§323.2(a)(1) (covering
traditionally navigable waters), (4) (covering tributaries of subsection
(a)(1) waters), and (7) (covering wetlands adjacent to subsection (a)(4)
waters).
8 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

Contrary to the plurality’s revisionist reading today,
ante, at 21–24, 28–29, Riverside Bayview nowhere implied
that our approval of “adjacent” wetlands was contingent
upon an understanding that “adjacent” means having a
“continuous surface connection” between the wetland and
its neighboring creek, ante, at 23. Instead, we acknowl
edged that the Corps defined “adjacent” as including
wetlands “ ‘that form the border of or are in reasonable
proximity to other waters’ ” and found that the Corps
reasonably concluded that adjacent wetlands are part of
the waters of the United States. 474 U. S., at 134 (quoting
42 Fed. Reg. 37128 (1977)). Indeed, we explicitly acknowl
edged that the Corps’ jurisdictional determination was
reasonable even though
“not every adjacent wetland is of great importance to
the environment of adjoining bodies of water. . . . If it
is reasonable for the Corps to conclude that in the ma
jority of cases, adjacent wetlands have significant ef
fects on water quality and the ecosystem, its defini
tion can stand. That the definition may include some
wetlands that are not significantly intertwined with
the ecosystem of adjacent waterways is of little mo
ment, for where it appears that a wetland covered by
the Corps’ definition is in fact lacking in importance to
the aquatic environment . . . the Corps may always al
low development of the wetland for other uses simply
by issuing a permit.” 474 U. S., at 135, n. 9.
In closing, we emphasized that the scope of the Corps’
asserted jurisdiction over wetlands had been specifically
brought to Congress’ attention in 1977, that Congress had
rejected an amendment that would have narrowed that
jurisdiction, and that even proponents of the amendment
would not have removed wetlands altogether from the
definition of “waters of the United States.” Id., at 135–
139.
 Cite as: 547 U. S. ____ (2006) 9

STEVENS, J., dissenting

Disregarding the importance of Riverside Bayview, the
plurality relies heavily on the Court’s subsequent opinion
in Solid Waste Agency of Northern Cook Cty. v. Army
Corps of Engineers, 531 U. S. 159 (2001) (SWANCC). In
stark contrast to Riverside Bayview, however, SWANCC
had nothing to say about wetlands, let alone about wet
lands adjacent to traditionally navigable waters or their
tributaries. Instead, SWANCC dealt with a question
specifically reserved by Riverside Bayview, see n. 3, supra,
namely, the Corps’ jurisdiction over isolated waters—
“ ‘waters that are not part of a tributary system to inter
state waters or to navigable waters of the United States,
the degradation or destruction of which could affect inter
state commerce.’ ” 531 U. S., at 168–169 (quoting 33 CFR
§323.2(a)(5) (1978); emphasis added); see also 531 U. S., at
163 (citing 33 CFR §328.2(a)(3) (1999), which is the later
regulatory equivalent to §323.2(a)(5) (1978)). At issue in
SWANCC was “an abandoned sand and gravel pit . . .
which provide[d] habitat for migratory birds” and con
tained a few pools of “nonnavigable, isolated, intrastate
waters.” 531 U. S., at 162, 166. The Corps had asserted
jurisdiction over the gravel pit under its 1986 Migratory
Bird Rule, which treated isolated waters as within its
jurisdiction if migratory birds depended upon these wa
ters. The Court rejected this jurisdictional basis since
these isolated pools, unlike the wetlands at issue in River
side Bayview, had no “significant nexus” to traditionally
navigable waters. 531 U. S., at 167. In the process, the
Court distinguished Riverside Bayview’s reliance on Con
gress’ decision to leave the Corps’ regulations alone when
it amended the Act in 1977, since “ ‘[i]n both Chambers,
debate on the proposals to narrow the definition of navi
gable waters centered largely on the issue of wetlands
preservation’ ” rather than on the Corps’ jurisdiction over
10 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

truly isolated waters. 531 U. S., at 170 (quoting 474 U. S.,
at 136).4
Unlike SWANCC and like Riverside Bayview, the cases
before us today concern wetlands that are adjacent to
“navigable bodies of water [or] their tributaries,” 474
U. S., at 123. Specifically, these wetlands abut tributaries
of traditionally navigable waters. As we recognized in
Riverside Bayview, the Corps has concluded that such
wetlands play important roles in maintaining the quality
of their adjacent waters, see id., at 134–135, and conse
quently in the waters downstream. Among other things,
wetlands can offer “nesting, spawning, rearing and resting
sites for aquatic or land species”; “serve as valuable stor

——————
4 As THE CHIEF JUSTICE observes, the Corps and the EPA initially

considered revising their regulations in response to SWANCC. Ante, at
1–2 (concurring opinion). THE CHIEF JUSTICE neglects to mention,
however, that almost all of the 43 States to submit comments opposed
any significant narrowing of the Corps’ jurisdiction—as did roughly
99% of the 133,000 other comment submitters. See U. S. General
Accounting Office, Report to the Chairman, Subcommittee on Energy
Policy, Natural Resources and Regulating Affairs, Committee on
Government Reform, House of Representatives, Waters and Wetlands:
Corps of Engineers Needs to Evaluate Its District Office Practices in
Determining Jurisdiction, GAO–04–297, pp. 14–15 (Feb. 2004),
http://www.gao.gov/new.items/d04297.pdf (hereinafter GAO Report) (all
Internet materials as visited June 14, 2006, and available in Clerk of
Court’s case file); Brief for Association of State and Interstate Water
Pollution Control Administrators as Amicus Curiae. In any event, the
agencies’ decision to abandon their rulemaking is hardly responsible for
the cases at hand. The proposed rulemaking focused on isolated
waters, which are covered by 33 CFR §328.3(a)(3) (1999) and which
were called into question by SWANCC, rather than on wetlands adja
cent to tributaries of navigable waters, which are covered by a combina
tion of §§328.3(a)(1), (5), and (7) and which (until now) seemed obvi
ously within the agencies’ jurisdiction in light of Riverside Bayview.
See 68 Fed. Reg. 1994 (2003) (“The agencies seek comment on the use
of the factors in 33 CFR 328.3(a)(3)(i)–(iii) . . . in determining
[Clean Water Act] jurisdiction over isolated, intrastate, non-navigable
waters”).
 Cite as: 547 U. S. ____ (2006) 11

STEVENS, J., dissenting

age areas for storm and flood waters”; and provide “sig
nificant water purification functions.” 33 CFR §320.4(b)(2)
(2005); 474 U. S., at 134–135. These values are hardly
“independent” ecological considerations as the plurality
would have it, ante, at 23—instead, they are integral to
the “chemical, physical, and biological integrity of the
Nation’s waters,” 33 U. S. C. §1251(a). Given that wet
lands serve these important water quality roles and given
the ambiguity inherent in the phrase “waters of the
United States,” the Corps has reasonably interpreted its
jurisdiction to cover non-isolated wetlands. See 474 U. S.,
at 131–135.5
This conclusion is further confirmed by Congress’ delib
erate acquiescence in the Corps’ regulations in 1977. Id.,
at 136. Both Chambers conducted extensive debates
about the Corps’ regulatory jurisdiction over wetlands,
rejected efforts to limit this jurisdiction, and appropriated
——————
5 Unsurprisingly, most Courts of Appeals to consider the scope of the

Corps’ jurisdiction after SWANCC have unhesitatingly concluded that
this jurisdiction covers intermittent tributaries and wetlands adja
cent—in the normal sense of the word—to traditionally navigable
waters and their tributaries. E.g., United States v. Deaton, 332 F. 3d
698 (CA4 2003) (upholding the Corps’ jurisdiction over wetlands adja
cent to a ditch that might not contain consistently flowing water but
did drain into another ditch that drained into a creek that drained into
a navigable waterway); Headwaters, Inc. v. Talent Irrigation Dist., 243
F. 3d 526 (CA9 2001) (treating as “waters of the United States” canals
that held water intermittently and connected to other tributaries of
navigable waters); United States v. Rueth Development Co., 335 F. 3d
598, 604 (CA7 2003) (observing “it is clear that SWANCC did not affect
the law regarding . . . adjacency” in upholding the Corps’ jurisdiction
over a wetland without finding that this wetland had a continuous
surface connection to its adjacent tributary); Baccarat Fremont v. U. S.
Army Corps of Engineers, 425 F. 3d 1150, 1156 (CA9 2005) (upholding
the Corps’ jurisdiction over wetlands separated by berms from tradi
tionally navigable channels and observing that “SWANCC simply did
not address the issue of jurisdiction over adjacent wetlands”); but see
In re Needham, 354 F. 3d 340 (CA5 2003) (reading “waters of the
United States” narrowly as used in the Oil Pollution Act of 1990).
12 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

funds for a “ ‘National Wetlands Inventory’ ” to help the
States “ ‘in the development and operation of programs
under this Act.’ ” Id., at 135–139 (quoting 33 U. S. C.
§1288(i)(2)). We found these facts significant in Riverside
Bayview, see 474 U. S., at 135–139, as we acknowledged in
SWANCC. See 531 U. S., at 170–171 (noting that
“[b]eyond Congress’ desire to regulate wetlands adjacent to
‘navigable waters,’ respondents point us to no persuasive
evidence” of congressional acquiescence (emphasis added)).
The Corps’ exercise of jurisdiction is reasonable even
though not every wetland adjacent to a traditionally navi
gable water or its tributary will perform all (or perhaps
any) of the water quality functions generally associated
with wetlands. Riverside Bayview made clear that juris
diction does not depend on a wetland-by-wetland inquiry.
474 U. S., at 135, n. 9. Instead, it is enough that wetlands
adjacent to tributaries generally have a significant nexus
to the watershed’s water quality. If a particular wetland
is “not significantly intertwined with the ecosystem of
adjacent waterways,” then the Corps may allow its devel
opment “simply by issuing a permit.” Ibid.6 Accordingly,
for purposes of the Corps’ jurisdiction it is of no signifi
cance that the wetlands in No. 04–1034 serve flood control
and sediment sink functions, but may not do much to trap
other pollutants, supra, at 4–5, and n. 2, or that the wet
land in No. 04–1328 keeps excess water from Lake St.
Clair but may not trap sediment, see supra, at 5–6.
Seemingly alarmed by the costs involved, the plurality
shies away from Riverside Bayview’s recognition that
jurisdiction is not a case-by-case affair. I do not agree
with the plurality’s assumption that the costs of preserv
ing wetlands are unduly high. It is true that the cost of
——————
6 Indeed, “[t]he Corps approves virtually all section 404 permit[s],”

though often requiring applicants to avoid or mitigate impacts to
wetlands and other waters. GAO Report 8.
 Cite as: 547 U. S. ____ (2006) 13

STEVENS, J., dissenting

§404 permits are high for those who must obtain them7—
but these costs amount to only a small fraction of 1% of
the $760 billion spent each year on private and public
construction and development activity. Sunding & Zil
berman 80. More significant than the plurality’s exagger
ated concern about costs, however, is the fact that its
omission of any discussion of the benefits that the regula
tions at issue have produced sheds a revelatory light on
the quality (and indeed the impartiality) of its cost-benefit
analysis.8 The importance of wetlands for water quality
is hard to overstate. See, e.g., U. S. Congress, Office
——————
7 According to the Sunding and Zilberman article cited by the plural

ity, ante, at 2, for 80% of permits the mean cost is about $29,000 (with a
median cost of about $12,000). The Economics of Environmental
Regulation by Licensing: An Assessment of Recent Changes to the
Wetland Permitting Process, 42 Natural Resources J. 59, 63, 74 (2002)
(hereinafter Sunding & Zilberman). Only for less than 20% of the
permits—those for projects with the most significant impacts on wet
lands—is the mean cost around $272,000 (and the median cost is
$155,000). Ibid.
Of course, not every placement of fill or dredged material into the
waters of the United States requires a §404 permit. Only when such
fill comes from point sources—“discernible, confined and discrete
conveyance[s]”—is a §404 permit needed. 33 U. S. C. §§1362(12), (14).
Moreover, permits are not required for discharges from point sources
engaged in, among other things, normal farming activities; mainte
nance of transportation structures; and construction of irrigation
ditches, farm roads, forest roads, and temporary mining roads.
§1344(f).
8 Rather than defending its own antagonism to environmentalism, the

plurality counters by claiming that my dissent is “policy-laden.” Ante,
at 28. The policy considerations that have influenced my thinking are
Congress’ rather than my own. In considering whether the Corps’
interpretation of its jurisdiction is reasonable, I am admittedly taking
into account the congressional purpose of protecting the physical,
chemical, and biological integrity of our waters. See 33 U. S. C.
§1251(a); see also Chevron U. S. A. Inc. v. Natural Resources Defense
Council, Inc., 467 U. S. 863, 837 (1984) (considering whether the agency
regulation was consistent with “the policy concerns that motivated the
[Clean Air Act’s] enactment”).
14 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

of Technology Assessment, Wetlands: Their Use and
Regulation, OTA–206, pp. 43–61 (Mar. 1984),
http://govinfo.library.unt.edu/ota/Ota_4/DATA/1984/8433.PDF
(hereinafter OTA) (describing wetlands’ role in floodpeak
reduction, shoreline protection, ground water recharge,
trapping of suspended sediment, filtering of toxic pollut
ants, and protection of fish and wildlife). See also ante, at
20 (KENNEDY, J., concurring in judgment). Unsurpris
ingly, the Corps’ approach has the overwhelming en
dorsement of numerous amici curiae, including 33 States
and the county in which the property in No. 04–1384 is
located.
In final analysis, however, concerns about the appropri
ateness of the Corps’ 30-year implementation of the Clean
Water Act should be addressed to Congress or the Corps
rather than to the Judiciary. Whether the benefits of
particular conservation measures outweigh their costs is a
classic question of public policy that should not be an
swered by appointed judges. The fact that large invest
ments are required to finance large developments merely
means that those who are most adversely affected by the
Corps’ permitting decisions are persons who have the
ability to communicate effectively with their representa
tives. Unless and until they succeed in convincing Con
gress (or the Corps) that clean water is less important
today than it was in the 1970’s, we continue to owe defer
ence to regulations satisfying the “evident breadth of
congressional concern for protection of water quality and
aquatic ecosystems” that all of the Justices on the Court in
1985 recognized in Riverside Bayview, 474 U. S., at 133.
III
Even setting aside the plurality’s dramatic departure
from our reasoning and holding in Riverside Bayview, its
creative opinion is utterly unpersuasive. The plurality
imposes two novel conditions on the exercise of the Corps’
 Cite as: 547 U. S. ____ (2006) 15

STEVENS, J., dissenting

jurisdiction that can only muddy the jurisdictional waters.
As JUSTICE KENNEDY observes, “these limitations . . . are
without support in the language and purposes of the Act
or in our cases interpreting it.” Ante, at 11 (opinion con
curring in judgment). The impropriety of crafting these
new conditions is highlighted by the fact that no party or
amicus has suggested either of them.9
First, ignoring the importance of preserving jurisdiction
over water beds that are periodically dry, the plurality
imposes a requirement that only tributaries with the
“relatively permanent” presence of water fall within the
Corps’ jurisdiction. Ante, at 13–14. Under the plurality’s
view, then, the Corps can regulate polluters who dump
dredge into a stream that flows year round but may not be
able to regulate polluters who dump into a neighboring
stream that flows for only 290 days of the year—even if
the dredge in this second stream would have the same
effect on downstream waters as the dredge in the year-
round one. Ante, at 14, n. 5.10
To find this arbitrary distinction compelled by the stat
ute, the plurality cites a dictionary for a proposition that it
does not contain. The dictionary treats “streams” as “wa
——————
9 Only 3 of the 21 amici briefs filed on petitioners’ behalf come even

close to asking for one of the plurality’s two conditions. These briefs
half-argue that intermittent streams should fall outside the Corps’
jurisdiction—though not for the reasons given by the plurality. See
Brief for National Stone, Sand and Gravel Assn. et al. 20, n. 7; Brief for
Foundation for Environmental and Economic Progress et al. 22–23;
Brief for Western Coalition of Arid States 10.
10 The plurality does suggest that “seasonal rivers” are not “necessar

ily exclude[d]” from the Corps’ jurisdiction—and then further suggests
that “streams” are “rivers.” Ante, at 14, n. 5. I will not explore the
semantic issues posed by the latter point. On the former point, I have
difficulty understanding how a “seasonal” river could meet the plural
ity’s test of having water present “relatively permanent[ly].” By failing
to explain itself, the plurality leaves litigants without guidance as to
where the line it draws between “relatively permanent” and “intermit
tent” lies.
16 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

ters” but has nothing to say about whether streams must
contain water year round to qualify as “streams.” Ante, at
13–14, and n. 6 (citing Webster’s New International Dic
tionary 2493 (2d ed. 1954) (hereinafter Webster’s Second),
as defining stream as a “ ‘current or course of water or
other fluid, flowing on the earth’ ”). From this, the plural
ity somehow deduces that streams can never be intermit
tent or ephemeral (i.e., flowing for only part of the
year). Ante, at 13–15, and nn. 5–6. But common
sense and common usage demonstrate that intermit-
tent streams, like perennial streams, are still
streams.11 See, e.g., U. S. Dept. of Interior, U. S. Geologi
cal Survey, Topographic Map Symbols 3 (2005),
http://erg.usgs.gov/isb/pubs/booklets/symbols/ (identifying
symbols for “[p]erennial stream” and “[i]ntermittent
stream,” as well as for “[p]erennial river” and
“[i]ntermittent river”). This was true well before the
passage of the Act in 1972. E.g., Webster’s Third New
International Dictionary 1180 (1961) (hereinafter Web
ster’s Third) (linking “intermittent” with “stream”). In
deed, we ourselves have used the term “intermittent
stream” as far back as 1932. Harrisonville v. W. S. Dickey
Clay Mfg. Co., 289 U. S. 334, 335 (1933). Needless to say,
Justice Brandeis’ use of the term in a unanimous opinion
should not be dismissed as merely a “useful oxymor[on],”
ante, at 15, n. 6 (plurality opinion).
The plurality attempts to bolster its arbitrary jurisdic
tional line by citing two tangential statutory provisions
——————
11 Indeed, in the 1977 debate over whether to restrict the scope of the
Corps’ regulatory power, Senator Bentsen recognized that the Corps’
jurisdiction “cover[s] all waters of the United States, including small
streams, ponds, isolated marshes, and intermittently flowing gullies.”
4 Legislative History of the Clean Water Act of 1977 (Committee Print
compiled for the Senate Committee on Environment and Public Works
by the Library of Congress), Ser. No. 95–14, p. 903 (1978). His pro
posed amendment to restrict this jurisdiction failed. Id., at 947.
 Cite as: 547 U. S. ____ (2006) 17

STEVENS, J., dissenting

and two inapplicable canons of construction. None comes
close to showing that Congress directly spoke to whether
“waters” requires the relatively permanent presence of
water.
The first provision relied on by the plurality—the defini
tion of “point source” in 33 U. S. C. §1362(14)—has no
conceivable bearing on whether permanent tributaries
should be treated differently from intermittent ones, since
“pipe[s], ditch[es], channel[s], tunnel[s], conduit[s], [and]
well[s]” can all hold water permanently as well as inter
mittently.12 The second provision is §1251(b), which an
nounces a congressional policy to “recognize, preserve, and
protect the primary responsibilities and rights of States”
to prevent pollution, to plan development, and to consult
with the EPA. Under statutory additions made in 1977
when Congress considered and declined to alter the Corps’
——————
12 The plurality’s reasoning to the contrary is mystifying. The plural

ity emphasizes that a ditch around a castle is also called a “moat” and
that a navigable manmade channel is called a “canal.” See ante, at 17,
n. 7. On their face (and even after much head-scratching), these points
have nothing to do with whether we use the word “stream” rather than
“ditch” where permanently present water is concerned. Indeed, under
the plurality’s reasoning, we would call a “canal” a “stream” or a “river”
rather than a “canal.”
Moreover, we do use words like “ditch” without regard to whether
water is present relatively permanently. In Jennison v. Kirk, 98 U. S.
453 (1879), for example, Justice Field used the term “ditch”—not
“stream”—in describing a manmade structure that carried water year
round. See also, e.g., Knoxville Water Co. v. Knoxville, 200 U. S. 22, 27
(1906) (opinion for the Court by Harlan, J.) (describing “pipes” that
would continuously carry water); ante, at 20, 24 (plurality opinion)
(using “channel” with reference to both intermittent and relatively
permanent waters); PUD No. 1 of Jefferson Cty. v. Washington Dept. of
Ecology, 511 U. S. 700, 709 (1994) (describing a “tunnel” that would
carry water year round); New Orleans Water-Works Co. v. Rivers, 115
U. S. 674, 683 (1885) (opinion for the Court by Harlan, J.) (describing
“conduits” that would supply water for a hotel). The plurality’s attempt
to achieve its desired outcome by redefining terms does no credit to
lexicography—let alone to justice.
18 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

interpretation of its broad regulatory jurisdiction, the
States may run their own §404 programs. §§1344(g)–(h).
As modified, §1251(b) specifically recognizes this role for
the States as part of their primary responsibility for pre
venting water pollution. Even focusing only on the Act as
it stood between 1972 and 1977, but see International
Paper Co. v. Ouellette, 479 U. S. 481, 489–490 (1987) (inter
preting §1251(b) in light of the 1977 additions), broad exer
cise of jurisdiction by the Corps still left the States with
ample rights and responsibilities. See S. D. Warren Co. v.
Maine Bd. of Environmental Protection, 547 U. S. __, __
(2006) (slip op., at 14–15). States had the power to impose
tougher water pollution standards than required by the
Act, §1370, and to prevent the Corps and the EPA from
issuing permits, §1341(a)(1)—not to mention nearly exclu
sive responsibility for containing pollution from nonpoint
sources.
The two canons of construction relied on by the plurality
similarly fail to overcome the deference owed to the Corps.
First, the plurality claims that concerns about intruding
on state power to regulate land use compel the conclusion
that the phrase “waters of the United States” does not
cover intermittent streams. As we have recognized, how
ever, Congress found it “ ‘essential that discharge of pol
lutants be controlled at the source,’ ” Riverside Bayview,
474 U. S., at 133 (quoting S. Rep. No. 92–414, p. 77
(1972)), and the Corps can define “waters” broadly to
accomplish this aim. Second, the plurality suggests that
the canon of constitutional avoidance applies because the
Corps’ approach might exceed the limits of our Commerce
Clause authority. Setting aside whether such a concern
was proper in SWANCC, 531 U. S., at 173; but see id., at
192–196 (STEVENS, J., dissenting), it is plainly not war
ranted here. The wetlands in these cases are not “iso
lated” but instead are adjacent to tributaries of tradition
ally navigable waters and play important roles in the
 Cite as: 547 U. S. ____ (2006) 19

STEVENS, J., dissenting

watershed, such as keeping water out of the tributaries or
absorbing water from the tributaries. “There is no consti
tutional reason why Congress cannot, under the commerce
power, treat the watersheds as a key to flood control on
navigable streams and their tributaries.” Oklahoma ex rel.
Phillips v. Guy F. Atkinson Co., 313 U. S. 508, 525 (1941).
Most importantly, the plurality disregards the funda
mental significance of the Clean Water Act. As then-
Justice Rehnquist explained when writing for the Court in
1981, the Act was “not merely another law” but rather was
“viewed by Congress as a ‘total restructuring’ and ‘com
plete rewriting’ of the existing water pollution legislation.”
Milwaukee v. Illinois, 451 U. S. 304, 317. “Congress’ intent
in enacting the [Act] was clearly to establish an all-
encompassing program of water pollution regulation,” and
“the most casual perusal of the legislative history demon
strates that . . . views on the comprehensive nature of the
legislation were practically universal.” Id., at 318, and
n. 12; see also 531 U. S., at 177–181 (STEVENS, J., dissent
ing). The Corps has concluded that it must regulate pol
lutants at the time they enter ditches or streams with
ordinary high-water marks—whether perennial, intermit
tent, or ephemeral—in order to properly control water
pollution. 65 Fed. Reg. 12823 (2000). Because there is
ambiguity in the phrase “waters of the United States” and
because interpreting it broadly to cover such ditches and
streams advances the purpose of the Act, the Corps’ ap
proach should command our deference. Intermittent
streams can carry pollutants just as perennial streams
can, and their regulation may prove as important for flood
control purposes. The inclusion of all identifiable tributar
ies that ultimately drain into large bodies of water within
the mantle of federal protection is surely wise.
The plurality’s second statutory invention is as arbi
trary as its first. Trivializing the significance of changing
conditions in wetlands environments, the plurality im
20 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

poses a separate requirement that “the wetland has a
continuous surface connection” with its abutting waterway
such that it is “difficult to determine where the ‘water’
ends and the ‘wetland’ begins.” Ante, at 24. An “intermit
tent, physically remote hydrologic connection” between the
wetland and other waters is not enough. Ibid. Under this
view, wetlands that border traditionally navigable waters
or their tributaries and perform the essential function of
soaking up overflow waters during hurricane season—
thus reducing flooding downstream—can be filled in by
developers with impunity, as long as the wetlands lack a
surface connection with the adjacent waterway the rest of
the year.
The plurality begins reasonably enough by recognizing
that the Corps may appropriately regulate all wetlands
“ ‘adjacent to’ ” other waters. Ante, at 21. This recognition
is wise, since the statutory text clearly accepts this stan
dard. Title 33 U. S. C. §1344(g)(1), added in 1977, in
cludes “adjacent wetlands” in its description of “waters”
and thus “expressly stated that the term ‘waters’ included
adjacent wetlands.” Riverside Bayview, 474 U. S., at 138.
While this may not “conclusively determine the construc
tion to be placed on the use of the term ‘waters’ elsewhere
in the Act . . . , in light of the fact that the various provi
sions of the Act should be read in pari materia, it does at
least suggest strongly that the term ‘waters’ as used in the
Act does not necessarily exclude ‘wetlands.’ ” Id., at 138,
n. 11.
The plurality goes on, however, to define “ ‘adjacent to’ ”
as meaning “with a continuous surface connection to”
other water. Ante, at 21–24. It is unclear how the plural
ity reached this conclusion, though it plainly neglected to
consult a dictionary. Even its preferred Webster’s Second
defines the term as “[l]ying near, close, or contiguous;
neighboring; bordering on” and acknowledges that
“[o]bjects are ADJACENT when they lie close to each other,
 Cite as: 547 U. S. ____ (2006) 21

STEVENS, J., dissenting

but not necessarily in actual contact.” Webster’s Second 32
(emphasis added); see also Webster’s Third 26. In any
event, the proper question is not how the plurality would
define “adjacent,” but whether the Corps’ definition is
reasonable.
The Corps defines “adjacent” as “bordering, contiguous,
or neighboring,” and specifies that “[w]etlands separated
from other waters of the United States by man-made dikes
or barriers, natural river berms, beach dunes and the like
are ‘adjacent wetlands.’ ” 33 CFR §328.3(c) (2005). This
definition is plainly reasonable, both on its face and in
terms of the purposes of the Act. While wetlands that are
physically separated from other waters may perform less
valuable functions, this is a matter for the Corps to evalu
ate in its permitting decisions. We made this clear in
Riverside Bayview, 474 U. S., at 135, n. 9—which did not
impose the plurality’s new requirement despite an absence
of evidence that the wetland at issue had the sort of con
tinuous surface connection required by the plurality today.
See supra, at 7; see also ante, at 15–17 (KENNEDY, J.,
concurring in judgment) (observing that the plurality’s
requirement is inconsistent with Riverside Bayview). And
as the facts of No. 04–1384 demonstrate, wetland sepa
rated by a berm from adjacent tributaries may still prove
important to downstream water quality. Moreover, Con
gress was on notice of the Corps’ definition of “adjacent”
when it amended the Act in 1977 and added 33 U. S. C.
§1344(g)(1). See 42 Fed. Reg. 37129 (1977).
Finally, implicitly recognizing that its approach endan
gers the quality of waters which Congress sought to pro
tect, the plurality suggests that the EPA can regulate
pollutants before they actually enter the “waters of the
United States.” Ante, at 24–27. I express no view on the
merits of the plurality’s reasoning, which relies heavily on
a respect for lower court judgments that is conspicuously
lacking earlier in its opinion, ante, at 8–10.
22 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

I do fail to understand, however, why the plurality
would not similarly apply this logic to dredged and fill
material. The EPA’s authority over pollutants (other than
dredged and fill materials) stems from the identical statu
tory language that gives rise to the Corps’ §404 jurisdic
tion. The plurality claims that there is a practical differ
ence, asserting that dredged and fill material “does not
normally wash downstream.” Ante, at 26. While more of
this material will probably stay put than is true of soluble
pollutants, the very existence of words like “alluvium” and
“silt” in our language, see Webster’s Third 59, 2119, sug
gests that at least some fill makes its way downstream.
See also, e.g., United States v. Deaton, 332 F. 3d 698, 707
(CA4 2003) (“Any pollutant or fill material that degrades
water quality in a tributary has the potential to move
downstream and degrade the quality of the navigable
waters themselves”). Moreover, such fill can harm the
biological integrity of downstream waters even if it largely
stays put upstream. The Act’s purpose of protecting fish,
see 33 U. S. C. §1251(a)(2); S. D. Warren Co., 547 U. S., at
__ (slip op., at 13–14), could be seriously impaired by
sediment in upstream waters where fish spawn, since
excessive sediment can “smother bottom-dwelling inverte
brates and impair fish spawning,” OTA 48. See also, e.g.,
Erman & Hawthorne, The Quantitative Importance of an
Intermittent Stream in the Spawning of Rainbow Trout,
105 Transactions of the American Fisheries Society 675–
681 (1976); Brief for American Rivers et al. as Amici Cu
riae 14 (observing that anadromous salmon often spawn in
small, intermittent streams).
IV
While I generally agree with Parts I and II–A of
JUSTICE KENNEDY’s opinion, I do not share his view that
we should replace regulatory standards that have been in
place for over 30 years with a judicially crafted rule dis
 Cite as: 547 U. S. ____ (2006) 23

STEVENS, J., dissenting

tilled from the term “significant nexus” as used in
SWANCC. To the extent that our passing use of this term
has become a statutory requirement, it is categorically
satisfied as to wetlands adjacent to navigable waters or
their tributaries. Riverside Bayview and SWANCC to
gether make this clear. SWANCC’s only use of the term
comes in the sentence: “It was the significant nexus be
tween the wetlands and ‘navigable waters’ that informed
our reading of the [Clean Water Act] in Riverside Bay-
view.” 531 U. S., at 167. Because Riverside Bayview was
written to encompass “wetlands adjacent to navigable
waters and their tributaries,” 474 U. S., at 123, and re
served only the question of isolated waters, see id., at 131–
132, n. 8; see also n. 3, supra, its determination of the
Corps’ jurisdiction applies to the wetlands at issue in
these cases.
Even setting aside the apparent applicability of River
side Bayview. I think it clear that wetlands adjacent to
tributaries of navigable waters generally have a “signifi
cant nexus” with the traditionally navigable waters down
stream. Unlike the “nonnavigable, isolated, intrastate
waters” in SWANCC, 531 U. S., at 171, these wetlands can
obviously have a cumulative effect on downstream water
flow by releasing waters at times of low flow or by keeping
waters back at times of high flow. This logical connection
alone gives the wetlands the “limited” connection to tradi
tionally navigable waters that is all the statute requires,
see id., at 172; 474 U. S., at 133—and disproves JUSTICE
KENNEDY’s claim that my approach gives no meaning to
the word “ ‘ navigable,’ ” ante, at 21 (opinion concurring in
judgment). Similarly, these wetlands can preserve down
stream water quality by trapping sediment, filtering toxic
pollutants, protecting fish-spawning grounds, and so forth.
While there may exist categories of wetlands adjacent to
tributaries of traditionally navigable waters that, taken
cumulatively, have no plausibly discernable relationship
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STEVENS, J., dissenting

to any aspect of downstream water quality, I am skeptical.
And even given JUSTICE KENNEDY’s “significant nexus”
test, in the absence of compelling evidence that many such
categories do exist I see no reason to conclude that the
Corps’ longstanding regulations are overbroad.
JUSTICE KENNEDY’s “significant nexus” test will proba
bly not do much to diminish the number of wetlands cov
ered by the Act in the long run. JUSTICE KENNEDY him
self recognizes that the records in both cases contain
evidence that “should permit the establishment of a sig
nificant nexus,” ante, at 27, see also ante, at 26, and it
seems likely that evidence would support similar findings
as to most (if not all) wetlands adjacent to tributaries of
navigable waters. But JUSTICE KENNEDY’s approach will
have the effect of creating additional work for all con
cerned parties. Developers wishing to fill wetlands adja
cent to ephemeral or intermittent tributaries of tradition
ally navigable waters will have no certain way of knowing
whether they need to get §404 permits or not. And the
Corps will have to make case-by-case (or category-by
category) jurisdictional determinations, which will inevi
tably increase the time and resources spent processing
permit applications. These problems are precisely the
ones that Riverside Bayview’s deferential approach avoid
ed. See 474 U. S., at 135, n. 9 (noting that it “is of little
moment” if the Corps’ jurisdiction encompasses some
wetlands “not significantly intertwined” with other waters
of the United States). Unlike JUSTICE KENNEDY, I see no
reason to change Riverside Bayview’s approach—and
every reason to continue to defer to the Executive’s sensi
ble, bright-line rule.
V
As I explained in SWANCC, Congress passed the Clean
Water Act in response to wide-spread recognition—based
on events like the 1969 burning of the Cuyahoga River in
 Cite as: 547 U. S. ____ (2006) 25

STEVENS, J., dissenting

Cleveland—that our waters had become appallingly
polluted. 531 U. S., at 174–175 (dissenting opinion). The
Act has largely succeeded in restoring the quality of
our Nation’s waters. Where the Cuyahoga River was
once coated with industrial waste, “[t]oday, that loca-
tion is lined with restaurants and pleasure boat
slips.” EPA, A Benefits Assessment of the Water
Pollution Control Programs Since 1972, p. 1–2 (Jan.
2000), http://www.epa.gov/ost/economics/assessment.pdf.
By curtailing the Corps’ jurisdiction of more than 30 years,
the plurality needlessly jeopardizes the quality of our
waters. In doing so, the plurality disregards the deference
it owes the Executive, the congressional acquiescence in
the Executive’s position that we recognized in Riverside
Bayview, and its own obligation to interpret laws rather
than to make them. While JUSTICE KENNEDY’s approach
has far fewer faults, nonetheless it also fails to give proper
deference to the agencies entrusted by Congress to imple
ment the Clean Water Act.
I would affirm the judgments in both cases, and respect
fully dissent from the decision of five Members of this
Court to vacate and remand. I close, however, by noting
an unusual feature of the Court’s judgments in these
cases. It has been our practice in a case coming to us from
a lower federal court to enter a judgment commanding
that court to conduct any further proceedings pursuant to
a specific mandate. That prior practice has, on occasion,
made it necessary for Justices to join a judgment that did
not conform to their own views.13 In these cases, however,
while both the plurality and JUSTICE KENNEDY agree that
——————
13 See, e.g., Screws v. United States, 325 U. S. 91, 131–134 (1945)

(Rutledge, J., concurring in result); Turner Broadcasting System, Inc. v.
FCC, 512 U. S. 622, 674 (1994) (STEVENS, J., concurring in part and
concurring in judgment); Hamdi v. Rumsfeld, 542 U. S. 507, 553–554
(2004) (SOUTER, J., concurring in part, dissenting in part, and concurring
in judgment).
26 RAPANOS v. UNITED STATES

STEVENS, J., dissenting

there must be a remand for further proceedings, their
respective opinions define different tests to be applied on
remand. Given that all four Justices who have joined this
opinion would uphold the Corps’ jurisdiction in both of
these cases—and in all other cases in which either the
plurality’s or JUSTICE KENNEDY’s test is satisfied—on
remand each of the judgments should be reinstated if
either of those tests is met.14

——————
14 I assume that JUSTICE KENNEDY’s approach will be controlling in

most cases because it treats more of the Nation’s waters as within the
Corps’ jurisdiction, but in the unlikely event that the plurality’s test is
met but JUSTICE KENNEDY’s is not, courts should also uphold the Corps’
jurisdiction. In sum, in these and future cases the United States may
elect to prove jurisdiction under either test.
 Cite as: 547 U. S. ____ (2006) 1

BREYER, J., dissenting

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 04–1034 and 04–1384
_________________

JOHN A. RAPANOS, ET UX., ET AL., PETITIONERS
04–1034 v.
UNITED STATES

JUNE CARABELL ET AL., PETITIONERS
04–1384 v.
UNITED STATES ARMY CORPS OF ENGINEERS ET AL.
ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE SIXTH CIRCUIT
[June 19, 2006]

JUSTICE BREYER, dissenting.
In my view, the authority of the Army Corps of Engi
neers under the Clean Water Act extends to the limits of
congressional power to regulate interstate commerce. See
Solid Waste Agency of Northern Cook Cty. v. Army Corps of
Engineers, 531 U. S. 159, 181–182 (2001) (SWANCC)
(STEVENS, J., dissenting). I therefore have no difficulty
finding that the wetlands at issue in these cases are within
the Corps’ jurisdiction, and I join JUSTICE STEVENS’ dissent
ing opinion.
My view of the statute rests in part upon the nature of the
problem. The statute seeks to “restore and maintain the
chemical, physical, and biological integrity of the Nation’s
waters.” 33 U. S. C. §1251(a). Those waters are so vari
ous and so intricately interconnected that Congress might
well have decided the only way to achieve this goal is to
write a statute that defines “waters” broadly and to leave
the enforcing agency with the task of restricting the scope
of that definition, either wholesale through regulation or
2 RAPANOS v. UNITED STATES

BREYER, J., dissenting

retail through development permissions. That is why I
believe that Congress, in using the term “waters of the
United States,” §1362(7), intended fully to exercise its
relevant Commerce Clause powers.
I mention this because the Court, contrary to my view,
has written a “nexus” requirement into the statute.
SWANCC, supra, at 167; ante, at 22 (opinion of KENNEDY,
J.) (“[T]he Corps’ jurisdiction over wetlands depends upon
the existence of a significant nexus between the wetlands
in question and navigable waters in the traditional
sense”). But it has left the administrative powers of the
Army Corps of Engineers untouched. That agency may
write regulations defining the term—something that it has
not yet done. And the courts must give those regulations
appropriate deference. Chevron U. S. A. Inc. v. Natural
Resources Defense Council, Inc., 467 U. S. 837 (1984).
If one thing is clear, it is that Congress intended the
Army Corps of Engineers to make the complex technical
judgments that lie at the heart of the present cases (sub
ject to deferential judicial review). In the absence of up
dated regulations, courts will have to make ad hoc deter
minations that run the risk of transforming scientific
questions into matters of law. That is not the system
Congress intended. Hence I believe that today’s opinions,
taken together, call for the Army Corps of Engineers to
write new regulations, and speedily so.