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

Syllabus

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,

Cite as: 547 U. S. ____ (2006) 3

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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).

4 RAPANOS v. UNITED STATES

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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.

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

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

2 RAPANOS v. UNITED STATES

Opinion of SCALIA, J.

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).

Cite as: 547 U. S. ____ (2006) 3

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

4 RAPANOS v. UNITED STATES

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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

Cite as: 547 U. S. ____ (2006) 7

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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

10 RAPANOS v. UNITED STATES

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.

Cite as: 547 U. S. ____ (2006) 11

Opinion of SCALIA, J.

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,

12 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 13

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.

14 RAPANOS v. UNITED STATES

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;

Cite as: 547 U. S. ____ (2006) 15

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

Cite as: 547 U. S. ____ (2006) 17

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

18 RAPANOS v. UNITED STATES

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.”

Cite as: 547 U. S. ____ (2006) 19

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.

20 RAPANOS v. UNITED STATES

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.

Cite as: 547 U. S. ____ (2006) 21

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

22 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 23

Opinion of SCALIA, J.

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).

24 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 25

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

26 RAPANOS v. UNITED STATES

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.

Cite as: 547 U. S. ____ (2006) 27

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

28 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 29

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).

30 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 31

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).

32 RAPANOS v. UNITED STATES

Opinion of SCALIA, J.

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

Cite as: 547 U. S. ____ (2006) 33

Opinion of SCALIA, J.

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.

34 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 35

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

36 RAPANOS v. UNITED STATES

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.”

Cite as: 547 U. S. ____ (2006) 37

Opinion of SCALIA, J.

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

Cite as: 547 U. S. ____ (2006) 5

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’

8 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 9

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

10 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 11

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

12 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 13

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

14 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 15

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

16 RAPANOS v. UNITED STATES

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.

Cite as: 547 U. S. ____ (2006) 17

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

18 RAPANOS v. UNITED STATES

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.

Cite as: 547 U. S. ____ (2006) 19

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

20 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 21

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.,

22 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 23

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

24 RAPANOS v. UNITED STATES

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

Cite as: 547 U. S. ____ (2006) 25

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

26 RAPANOS v. UNITED STATES

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

This text is long and has been trimmed here. Open the source document for the complete record.