 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued April 9, 2015              Decided September 29, 2015

                        No. 14-5205

                       SIERRA CLUB,
                        APPELLANT

                             v.

    UNITED STATES ARMY CORPS OF ENGINEERS, ET AL.,
                     APPELLEES


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:13-cv-01239)


    Douglas P. Hayes argued the cause for appellant. With
him on the briefs were Eric E. Huber and Joshua Stebbins.

    Michael T. Gray, Attorney, U.S. Department of Justice,
argued the cause for Federal appellees. With him on the brief
were John C. Cruden, Assistant Attorney General, and Ty
Bair and David C. Shilton, Attorneys.

    David H. Coburn and Cynthia Taub were on the brief for
appellee Enbridge Pipelines (FSP), L.L.C. Joshua H. Runyan
entered an appearance.

    Before: BROWN, PILLARD and WILKINS, Circuit Judges.
                               2
    Opinion for the Court filed by Circuit Judge PILLARD.

    Opinion concurring in the judgment filed by Circuit
Judge BROWN.

     PILLARD, Circuit Judge: The central question in this
appeal is the scope of environmental review the National
Environmental Policy Act (NEPA) required before a
particular oil pipeline was built. Oil pipelines help to satisfy
national and global energy demand by pumping tens of
millions of barrels of oil across the United States each month.
They have also sparked intense debates about energy and
environmental policies. The proposed Keystone XL Pipeline
alone has generated millions of comments to the government
on a spectrum of issues. The construction and operation of
pipelines necessarily affect land, water, air, plants, animals,
and human life, and carry the potential for unintended
damage. More than a dozen pipeline accidents occur on
average each month in the United States—most minor, some
grave. If not transported via pipelines, oil might remain in the
ground and never be used, or might be brought to market in
other ways—potentially by methods less efficient and more
harmful than pipeline transportation.

      The U.S. Secretary of State must approve oil pipelines
that cross international borders, see Exec. Order 11,423, 33
Fed. Reg. 11,741 (Aug. 16, 1968), but that requirement is
inapplicable to wholly domestic pipelines. Separately, the
Pipeline and Hazardous Materials Safety Administration
(PHMSA) within the U.S. Department of Transportation must
approve oil spill response plans under the Oil Pollution
Control Act of 1990 for pipelines that might spill oil into
navigable waters or the shoreline, see 33 U.S.C. §
1321(j)(5)(A)(i), (C)(iv), (G); Executive Order 12,777, 56
Fed. Reg. 54,757, 54,760 (Oct. 18, 1991), 49 C.F.R. § 194.7,
                                3
but there is no claim here PHMSA must approve a response
plan before a pipeline can be built and begin operating.1

     Notwithstanding the absence of any general permitting
requirement for domestic oil pipelines, federal ownership or
control of lands and other assets, as well as resource-specific
environmental statutes such as the Clean Water Act, often do
call for federal approvals before an oil pipeline can be built.
Where there is federal action, NEPA requires governmental
review, with public input, of the full range of such action’s
reasonably foreseeable direct or indirect environmental
effects. Federal actions subject to NEPA include federal
authorizations granted to private parties, such as oil pipeline
construction companies.

    The Flanagan South oil pipeline pumps crude oil across
593 miles of American heartland from Illinois to Oklahoma.
Almost all of the land over which it passes is privately owned.
As soon as Enbridge Pipelines (FSP), LLC, (Enbridge) began
building the pipeline in 2013, the Sierra Club, a national
environmental nonprofit organization, sued the federal
government seeking to set aside several federal agencies’
regulatory approvals relating to the pipeline and to enjoin the
pipeline’s construction and operation in reliance on any such
approvals.

    Sierra Club’s chief claim was that various federal
easements and approvals that Enbridge obtained from the
agencies gave necessary go-ahead to the Flanagan South
project as a whole, and thus the entire pipeline was a
foreseeable effect of federal action requiring public
environmental scrutiny under NEPA. Sierra Club also

1
  The complaint asserted a PHMSA-related NEPA claim, but the
district court dismissed that claim for lack of final agency action
because no oil spill response plan had been finalized.
                               4
claimed that one of the agencies, the United States Army
Corps of Engineers (the Corps), unlawfully authorized dredge
and fill activities at the pipeline’s nearly two thousand minor
water crossings by verifying that they fell within the authority
of a general permit, Nationwide Permit 12, that the Corps had
promulgated under the Clean Water Act. Sierra Club argued
that the Corps impermissibly conducted its analyses of the
water crossings’ cumulative impacts by region, rather than
considering the pipeline as a whole, and that its conclusions
that the crossings would have only minimal adverse
environmental effects were inadequately supported and
conclusory. After Sierra Club filed suit, Enbridge promptly
intervened as a defendant.           The district court denied
preliminary injunctive relief and entered summary judgment
in favor of the agencies and Enbridge.

     On appeal, Sierra Club principally contends that the
district court erred by failing to require the agencies to
analyze and invite public comment on the environmental
impact of the whole pipeline under NEPA, including the
lengthy portions crossing private land and not otherwise
subject to federal approvals. Sierra Club also presses its
challenge to the Corps’s Clean Water Act verifications of the
pipeline’s many water crossings. Sierra Club further contends
that the district court reversibly erred by failing to allow the
organization to supplement and amend its complaint. Sierra
Club’s proposed new complaint added claims that the Corps
and the Bureau of Indian Affairs within the U.S. Department
of the Interior (the Bureau) had, while the litigation was
pending, completed separate NEPA analyses relating to each
of the easements the agencies had granted for the pipeline to
cross federally controlled land, and that those analyses were
insufficient.
                               5
     We hold that the federal government was not required to
conduct NEPA analysis of the entirety of the Flanagan South
pipeline, including portions not subject to federal control or
permitting. The agencies’ respective regulatory actions—in
the form of easements, Clean Water Act verifications, and
authorization to harm or kill members of endangered species
without incurring liability under the Endangered Species Act
(ESA)—were limited to discrete geographic segments of the
pipeline comprising less than five percent of its overall length.
As explained below, the agencies were required to conduct
NEPA analysis of the foreseeable direct and indirect effects of
those regulatory actions. However, on the facts of this case,
the agencies were not obligated also to analyze the impact of
the construction and operation of the entire pipeline.       We
also reject Sierra Club’s Clean Water Act challenge to the
Corps’s verifications of Flanagan South’s water crossings
under Nationwide Permit 12 because the Corps was
authorized to conduct its review on a regional rather than
nationwide basis, and the Corps’s District Managers
adequately supported their verification decisions. Finally, we
hold that the district court did not abuse its discretion in
denying Sierra Club’s motion to supplement and amend its
complaint, because the proposed new allegations would not
have affected the dispositive legal analysis.

                       I.   Background

               A.    Flanagan South Planning

     Enbridge began the planning and permitting process for
the Flanagan South project in 2011. The 593-mile-long
pipeline was designed to ship roughly 600,000 barrels of oil
per day across Illinois, Missouri, Kansas, and Oklahoma. The
new pipeline would expand Enbridge’s capacity to ship crude
oil from Flanagan, Illinois, to a major terminal in Cushing,
                               6
Oklahoma. From Cushing, the oil was to flow to refineries on
the Gulf Coast and elsewhere. Enbridge designed the pipeline
to run parallel to an existing pipeline, the Spearhead pipeline,
which had been in operation since 2006.

     Roughly four-fifths of Flanagan South would track within
50 feet of the existing Spearhead pipeline. Most of the 36”-
diameter Flanagan South pipeline was to be buried at least
four feet underground in trenches dug approximately ten feet
wide and deep. As planned, the pipeline would pass
underneath roads and streambeds and cross approximately
400 miles of farmland, 85 miles of forests, 68 miles of
grasslands, 28 miles of developed land, and 10 miles of
wetlands. Flanagan South’s construction would require
grading, excavation, or other forms of earth-disturbing
activities in order to erect, inspect, and maintain the pipeline
itself and its supporting infrastructure, such as pumping
stations, mainline valves, pipe yards and access roads. The
construction activities would affect swaths of land as wide as
135 feet, and ongoing maintenance would use a permanent
50-foot-wide right of way, kept clear by cutting back
vegetation every three to five years and possible application
of herbicides. Of the sixty eight miles of access roads
anticipated for the pipeline, roughly seven miles would be
newly constructed, with most of the new roads crossing non-
forested, agricultural areas not requiring tree removal.

    Enbridge budgeted more than $2.5 billion to build
Flanagan South and sought to complete construction by June
2014, only ten months after breaking ground. Before starting
construction, Enbridge negotiated rights of way across
approximately 2,400 tracts of land owned by approximately
1,700 private landowners. The company conducted public
outreach campaigns and solicited input from local officials,
Indian nations, community groups, and landowners expected
                              7
to be affected by the project. Enbridge also sought regulatory
authorizations from local and state governmental entities, as
well as federal agencies.

     The parties do not dispute that, to complete construction
of the pipeline, Enbridge required easements from the Corps
and the Bureau to cross spans of federal and Indian lands, and
Clean Water Act approvals from the Corps to conduct dredge
and fill activities at water crossings. The parties also
recognize that, in granting those permissions, the Corps and
Bureau were required to consult with the U.S. Fish and
Wildlife Service (the Service) pursuant to Section 7 of the
ESA regarding the harm to endangered or threatened species
anticipated to result from those permissions. They further
recognize that Enbridge could not lawfully harm listed species
unless it obtained either a safe harbor from the Section 7
consultation process, see 16 U.S.C. § 1536, or a permit under
Section 10 of the ESA, see id. § 1539, discussed below.

     Enbridge urged the agencies to act quickly so that it
could meet its construction deadlines, and the agencies did so.
Enbridge obtained Clean Water Act verifications from the
Corps for the pipeline to make water crossings, as well as
easements from the Corps and the Bureau to cross federal and
Indian lands. The Corps and Bureau also consulted with the
Service pursuant to ESA Section 7 regarding their approvals’
potential impact on listed species, and the Service issued a
Biological Opinion regarding the Flanagan South project’s
anticipated impact.

     The Biological Opinion concluded that building and
operating Flanagan South would likely result in some
“take”—i.e., harming or killing—of two listed, endangered
species, the Indiana Bat and the American Burying Beetle, but
that the take would not be so extensive as to jeopardize the
                                   8
continued existence of either species.2 The Biological
Opinion contained an Incidental Take Statement (ITS) that
identified reasonable and prudent measures, chiefly habitat
restoration and monitoring measures, by which Enbridge
could minimize the anticipated take of the two species that
would occur incidental to the project, and set forth mandatory
terms and conditions to that end. The ITS provided Enbridge
a conditional safe harbor from liability under the ESA for any
taking of listed species, but that permission was limited: By
its own terms, it was valid only insofar as the Corps or Bureau
imposed the ITS on Enbridge by incorporating it as a binding,
enforceable term of permits or contracts they issued to
Enbridge to which Enbridge in fact adhered. The easements
that the Corps and Bureau granted to Enbridge did not purport
to incorporate and enforce the ITS, and the Corps’s
verifications did so only within the geographic segments of
the Corps’s Clean Water Act jurisdiction over the verified
water crossing areas. Enbridge considered but decided
against applying to the Service for a Section 10 permit to take
species, instead of or in addition to obtaining the safe harbor
resulting from the verifications’ incorporation of the Section 7
ITS.

    The Corps conducted a NEPA analysis when it reissued
Nationwide Permit 12, see 77 Fed. Reg. 10,184, 10,197 (Feb.

2
  The Indiana bat is a medium-sized migratory bat found in the
eastern United States that faces threats to its habitat for hibernation,
roosting, forage, migration and swarming. It has been listed as an
endangered species since 1967, when it was originally listed under
the Endangered Species Preservation Act of 1966, a predecessor to
the ESA. 32 Fed. Reg. 4,001 (Mar. 11, 1967). The American
Burying Beetle is a uniquely large, colorful beetle, found chiefly in
a few central states, whose numbers have been depleted due largely
to the fragmentation of its habitat. It has been listed as endangered
since 1989. 54 Fed. Reg. 29,652 (July 13, 1989).
                              9
21, 2012), and the Corps and the Bureau each completed
geographically limited NEPA analyses in conjunction with
the easements they granted. No agency performed a NEPA
analysis of the full Flanagan South project.

    B. NEPA’s Environmental Review Requirement

     NEPA requires the federal government to identify and
assess in advance the likely environmental impact of its
proposed actions, including its authorization or permitting of
private actions. Dep’t of Transp. v. Pub. Citizen, 541 U.S.
752, 756-57 (2004). NEPA’s mandate, which incorporates
notice and comment procedures, serves the twin purposes of
ensuring that (1) agency decisions include informed and
careful consideration of environmental impact, and (2)
agencies inform the public of that impact and enable
interested persons to participate in deciding what projects
agencies should approve and under what terms. Id. at 768.
The statute serves those purposes by requiring federal
agencies to take a “hard look” at their proposed actions’
environmental consequences in advance of deciding whether
and how to proceed. Robertson v. Methow Valley Citizens
Council, 490 U.S. 332, 350-51 (1989). The statute does not
dictate particular decisional outcomes, but “merely prohibits
uninformed—rather than unwise—agency action.” Id. at 351;
see also Pub. Citizen, 541 U.S. at 756-57.

     At the heart of NEPA is the procedural requirement that
federal agencies prepare and make publicly available, in
anticipation of proposed “major Federal actions significantly
affecting the quality of the human environment,” an
Environmental Impact Statement (EIS) that assesses the
action’s anticipated direct and indirect environmental effects,
and that the agencies consider alternatives that might lessen
any adverse environmental impact. 42 U.S.C. § 4332(C); 40
                              10
C.F.R. § 1508.11. Regulations promulgated by the Council
on Environmental Quality (CEQ) provide common guidance
for all federal agencies in carrying out their NEPA
responsibilities. Pub. Citizen, 541 U.S. at 757; see 40 C.F.R.
pts. 1501-02. Some agencies, such as the Corps, have
promulgated their own, complementary NEPA regulations in
order to provide additional guidance to their personnel to
carry out the directives of the statute and the CEQ regulations
in agency-specific contexts. See, e.g., 33 C.F.R. § 325 App. B
(Corps regulations); see also 40 C.F.R. § 1500.2(a)-(b).

     The CEQ regulations explain that NEPA’s “federal
actions” may encompass the federal government’s own
undertakings, such as promulgating a rule or building a public
project, as well as government authorizations or support of
non-federal activities, such as approving private construction
activities “by permit or other regulatory decision.” 40 C.F.R.
§ 1508.18(a), (b)(4). The CEQ regulations clarify that the
term “major” “reinforces but does not have a meaning
independent of significantly,” 40 C.F.R. § 1508.18, and
explain that interpretation of the term “significantly” entails
case-by-case consideration of the context of the action and the
severity of its impact, id. § 1508.27.

     When it is uncertain whether a proposed federal action
will “significantly affect” the environment so as to require an
EIS, the regulations call for the agency to prepare an
Environmental Assessment (EA)—essentially, a preliminary
consideration of potential environmental effects in a “concise
public document” designed to “provide sufficient evidence
and analysis for determining whether” an EIS is needed. Id.
§§ 1501.4(b)-(c), 1508.9; see Pub. Citizen, 541 U.S. at 757-
58. If, informed by the EA, the agency finds no need for an
EIS, it must prepare a “finding of no significant impact”
(FONSI) that includes or summarizes the EA and briefly
                              11
explains why the agency believes the action will not have a
significant effect on the environment.             40 C.F.R.
§§ 1501.4(e), 1508.13. For example, the EAs performed by
the Corps and the Bureau in this case assessed the anticipated
environmental effects—on soil, water, species, air quality,
noise, and cultural resources—of granting Enbridge’s
requested easements to run Flanagan South across the federal
lands. The agencies’ EAs resulted in a FONSI for each
easement. Each form of NEPA analysis—EA/FONSI or
EIS—requires public notice and comment, id. §§ 1503.1,
1501.4(e), 1506.6, and each is subject to judicial review, see,
e.g., Pub. Citizen, 541 U.S. at 763-64; Grand Canyon Trust v.
FAA, 290 F.3d 339, 340-42 (D.C. Cir. 2002).

     Sierra Club’s objection in this suit concerns the scope,
not the intensiveness, of the agencies’ analyses. That is,
Sierra Club does not complain that an agency improperly
prepared an EA and issued a FONSI when it should have
prepared an EIS. Rather, it complains that no agency ever
conducted pipeline-wide NEPA analysis to any degree,
whether an EA or an EIS.

     Sierra Club identifies three groups of federal agency
approvals that, it contends, support its claim that federal law
requires a pipeline-wide NEPA analysis of the Flanagan
South project: (1) easements granted by the Corps and the
Bureau for the pipeline to span two parcels of federally owned
riverside land and 34 parcels of federally managed Indian
lands; (2) Clean Water Act verifications issued by the Corps
concluding that 1,950 water crossings complied with the
Clean Water Act under Nationwide Permit 12; and (3)
conditional permission for Enbridge to take endangered
species in the course of constructing and maintaining the
pipeline without incurring liability under the ESA—
permission provided through an Incidental Take Statement,
                              12
issued by the Service and implemented by the Corps in its
verifications.   Sierra Club contends that those actions
triggered a requirement under NEPA that one of the agencies
review the environmental impact of the entire pipeline,
including portions outside the segments that the federal
actions purported to address.

      1.    Easements Across Federal or Indian Lands

     Both the Corps and the Bureau granted Enbridge
easements to cross federal and Indian lands. See 30 U.S.C.
§ 185(a) (authorizing agencies to issue rights of way for
transportation of oil and gas across federal lands); 25 U.S.C. §
321 (authorizing the Department of the Interior to issue rights
of way for oil and gas transportation across Indian lands).
The Corps easements allowed the pipeline to cross 1.3 miles
of land in two parcels owned by the federal government along
the Mississippi and Arkansas Rivers. The Bureau easements
afforded rights of way across 34 tracts, or 12.3 total miles, of
Indian lands the Bureau manages in trust for tribes. The
Corps and Bureau prepared three discrete NEPA analyses, in
the form of EAs, to consider the anticipated environmental
effects of granting Enbridge rights to construct segments of
the pipeline across those lands. Each analysis considered only
the environmental impact anticipated within its respective
geographic area.

           2.   Clean Water Act Verifications Under
                     Nationwide Permit 12

     The next category of federal actions involved
verifications by the Corps, which authorized the Flanagan
South pipeline to cross minor waterways consistent with the
Clean Water Act.        The Corps has responsibility for
implementing the provisions of the Act relevant here,
including by requiring permits for construction activities that
                               13
involve dredge and fill of water features (including wetlands)
subject to the Act’s jurisdiction. See 33 U.S.C. § 1344. The
Corps grants Clean Water Act permits in one of two ways: It
issues individual permits that are tailored to specific projects,
id. § 1344(a), or it promulgates general permits, such as
Nationwide Permit 12, and later “verifies” that specific
manifestations of a generally approved type of project, such
as crossings by pipelines and other utility lines, qualify
thereunder, see id. § 1344(e); see also Reissuance of
Nationwide Permits, 77 Fed. Reg. 10,184, 10,271-72 (Feb. 21,
2012).

      General permits authorize categories of actions that will,
alone and together, cause only minimal adverse
environmental effects. 33 U.S.C. § 1344(e). They may
extend to activities throughout a state, a region, or the nation;
must be reevaluated at least every five years if they are to be
reissued; and may contain general conditions applicable to all
projects subject to approval thereunder. See id. Nationwide
Permit 12 “addresses the construction, maintenance, repair,
and removal of all utility lines throughout the nation,”
including lines “carrying resources (like water, fuel, and
electricity), facilitating communication (like telephone lines,
internet connections, and cable television), and removing
waste.” Sierra Club, Inc. v. Bostick, 787 F.3d 1043, 1058
(10th Cir. 2015); see also 77 Fed. Reg. at 10,271-72 (broadly
defining “utility line” to include “any pipe or pipeline for the
transportation of any gaseous, liquid, liquescent, or slurry
substance, for any purpose, and any cable, line, or wire for the
transmission for any purpose of electrical energy, telephone,
and telegraph messages, and radio and television
communication”). There is no dispute that the Flanagan
South oil pipeline qualifies as a “utility line” under
Nationwide Permit 12. Nationwide Permit 12 authorizes
utility line construction activities that affect no more than a
                              14
half-acre of jurisdictional waters at any single crossing. See
77 Fed. Reg. at 10,271, 10,290.

     After the Corps has promulgated a general permit, with
public notice and an opportunity for a hearing, regional staff
members consider requests for “verifications” of projects
thereunder. For a project to qualify for verification under a
general permit, a Corps District Engineer must conclude that
it complies with the general permit’s conditions, will cause no
more than minimal adverse effects on the environment, and
will serve the public interest. 33 C.F.R. §§ 330.1(e)(2),
330.6(a)(3)(i).     Because the Corps cannot accurately
anticipate the effects of thousands of future activities at the
time it promulgates a general permit, the general permit’s
basic terms may later be supplemented by a Corps District
Engineer’s decision to attach additional, project-specific
conditions at the verification stage. 33 C.F.R. §§ 330.1(e)(2),
330.6(a)(3)(i); see also Ohio Valley Envtl. Coal. v. Bulen, 429
F.3d 493, 501 (4th Cir. 2005). If a District Engineer deems a
project inappropriate for verification under a general permit,
the engineer may require that the project instead proceed
under an individual permit. 33 C.F.R. § 330.6(a)(2), (d).

     In this case, four regional Corps offices each issued
verifications of the Flanagan South project for their respective
regions under Nationwide Permit 12. The 1,950 crossings the
Corps verified here collectively comprise about 13.7 miles, or
roughly 2.3 percent, of the Flanagan South pipeline’s 593-
mile route. The Corps did not require any separate permits. It
did, however, impose conditions on the verifications to ensure
compliance with the Endangered Species Act, as
contemplated by the Clean Water Act’s minimal-adverse-
impacts requirement.
                                 15
     The Corps performed a NEPA analysis when it
promulgated Nationwide Permit 12, and Sierra Club does not
here challenge the adequacy of the Corps’s analysis at that
stage. See 77 Fed. Reg. at 10,187. The Corps did not conduct
any further NEPA analysis of its verifications of Flanagan
South under the nationwide permit. The Corps’s practice is to
perform NEPA analysis for general permits in advance of
their promulgation, and not to conduct additional NEPA
analysis when it verifies specific activities under the general
permits. See, e.g., Bostick, 787 F.3d at 1054;3 Snoqualmie
Valley Pres. All. v. U.S. Army Corps of Eng’rs, 683 F.3d
1155, 1158 (9th Cir. 2012). The Corps represented to this
court that it is very common for domestic oil pipelines to be
constructed without any whole-pipeline NEPA analysis, and
estimates that 180 oil pipelines have been constructed
primarily over private lands without analysis of the
environmental effects of the pipeline as a whole.

                3. Endangered Species Act
               Consultation and Authorization

     The third type of federal action at issue is the conditional,
limited authorization of the Flanagan South pipeline under the
Endangered Species Act. Following interagency consultation
required by Section 7 of the ESA in connection with federal
agency actions, the Service issued and the Corps implemented

3
  For thoughtful analysis of the scope of the Corps’s obligations
under NEPA, see Bostick, 787 F.3d at 1062 (McHugh, J.,
concurring). To the extent that the Corps, both in Bostick, see id. at
1062-63, and in this case, see Oral Arg. Rec. (Apr. 9, 2015) 30:20-
31:37, understood its NEPA obligations as confined to considering
environmental effects on CWA jurisdictional waters, its view
misapprehends the obligations of any agency taking action subject
to NEPA to do a comprehensive analysis of all types of foreseeable
environmental effects. See 40 C.F.R. §§ 1508.8, 1508.27.
                              16
an Incidental Take Statement to minimize the project’s impact
on two endangered species, the Indiana Bat and the American
Burying Beetle, and to authorize incidental take of those
species.

     When Congress enacted the ESA, it “intended
endangered species to be afforded the highest of priorities.”
Tenn. Valley Auth. v. Hill, 437 U.S. 153, 174 (1978); see
generally 16 U.S.C. § 1531. The ESA generally prohibits the
“take” of any members of endangered animal species,
defining “take” as “to harass, harm, pursue, hunt, shoot,
wound, kill, trap, capture, or collect, or to attempt to engage
in any such conduct.” 16 U.S.C. §§ 1532(19), 1538(a)(1)(B).
Notwithstanding that prohibition, private parties such as
Enbridge may obtain authorization for incidental take of
species where the take is not the project’s objective and is
sufficiently limited that it does not jeopardize the survival of
the species. See id. §§ 1536(a)(2), 1539(a)(2)(B). A party
may obtain such limited permission for the incidental take of
species in either of two ways.

     First, a party may apply to the Service for a permit under
Section 10 of the ESA, and the Service may issue a permit
directly to that party to take members of listed species “if
such taking is incidental to, and not the purpose of, the
carrying out of an otherwise lawful activity.”             Id. §
1539(a)(1)(B); see, e.g., Gerber v. Norton, 294 F.3d 173, 175
(D.C. Cir. 2002) (Service issuing Section 10 permit to a
developer to take endangered fox squirrels incidental to
constructing a residential housing project). A Section 10
permit application must include a conservation plan that
specifies the likely impact of the anticipated take as well as
steps for minimizing and mitigating such impact (with
identified funding sufficient to implement those steps), and
that identifies which potentially less harmful alternatives were
                               17
considered and why they are not being used. 16 U.S.C.
§ 1539(a)(2)(A). Enbridge considered and decided against
seeking a Section 10 permit, as detailed below.

     Second, and less directly, a private party may take listed
species by complying with an ITS issued by the Service
pursuant to ESA Section 7. Section 7 requires other federal
agencies to consult with the Service whenever they have
reason to believe that listed species or critical habitats may be
affected by their planned actions, including authorizations of
private parties’ actions. Id. § 1536(a). Accordingly, in this
case the Corps and the Bureau, as “action agencies,”
consulted with the Service in light of the Clean Water Act
verifications that the Corps was issuing and the easements
that both agencies were granting to Enbridge. See id.; see
generally U.S. Fish & Wildlife Serv. & Nat’l Marine
Fisheries Serv., Endangered Species Consultation Handbook
(March 1998) (hereinafter “Section 7 Handbook”),
http://www.fws.gov/endangered/esa-library/pdf/
esa_section7_handbook.pdf. The Service allows private
parties to participate in a Section 7 consultation when the
contemplated action involves the action agency’s approval of
private-party conduct, see 16 U.S.C. § 1536(b); 50 C.F.R. §
402.14, and Enbridge actively participated in the ESA Section
7 consultation relating to Flanagan South.

     In a Section 7 consultation, the Service prepares a
Biological Opinion identifying the project and any likely
impact on listed species or their habitat. 16 U.S.C. § 1536(a)-
(c); 50 C.F.R. §§ 402.02, 402.14(e), (g)-(h). The Service
cannot approve proposed actions that are likely to jeopardize
the continued existence of listed species or critical habitats.
16 U.S.C. §§ 1536(a)(2), (b)(4). If an action will likely result
in at most a limited take that is incidental to the project, the
Service provides the consulting agency and private party with
                               18
an ITS as part of the Biological Opinion. Id.; 50 C.F.R.
§ 402.14(i). An ITS identifies reasonable and prudent
measures—such as mitigation, monitoring, and reporting—
necessary or appropriate to minimize the impact on species
likely to be incidentally affected by the project, and terms and
conditions required to implement those measures. 16 U.S.C.
§ 1536(b)(4); 50 C.F.R. § 402.14(i)(1)(ii), (iv); see, e.g., San
Luis & Delta-Mendota Water Auth. v. Jewell, 747 F.3d 581,
597-99 (9th Cir. 2014), cert. denied, 135 S. Ct. 948 (2015).

     It is up to an action agency that has consulted with the
Service under Section 7 to determine whether and how to
proceed with its proposed action (including permitting private
activity) in light of an ITS issued by the Service. 50 C.F.R. §
402.15(a); see 16 U.S.C. § 1536(b)(4). However, the action
agency and private party (unless it has obtained a Section 10
permit) must comply with the Service’s ITS if they wish to be
insulated from ESA liability for taking species incidental to
the project. 16 U.S.C. § 1536(o)(2); 50 C.F.R. § 402.14(i)(5);
see, e.g., Bennett v. Spear, 520 U.S. 154, 169-70 (1997).

     In this case, the Service consulted with the Corps and the
Bureau, and Enbridge participated.           The agencies and
Enbridge negotiated for more than a year over several
questions, including whether Enbridge would seek a Section
10 permit or a Section 7 ITS; whether the Biological Opinion
and its ITS would cover only the verification and easement
areas or the whole Flanagan South project; and the geographic
extent to which the Corps was responsible for incorporating
the ITS in its verifications and enforcing it outside those
jurisdictional areas. The Service ultimately prepared a
Biological Opinion that examined the entire length of the
pipeline. See 50 C.F.R. § 402.02 (“Action area means all
areas to be affected directly or indirectly by the Federal action
and not merely the immediate area involved in the action.”).
                               19
Neither the Service nor the Corps or Bureau prepared any
NEPA analysis of the issuance or implementation of the ITS.

     The Service determined that, if Enbridge took certain
mitigation measures and performed onsite monitoring for five
decades, the project would result in a tolerable degree of
incidental take of the two identified endangered species and
their critical habitat. The Service so specified in the ITS it
issued pursuant to Section 7. If the ITS were made a binding
condition of a contract, permit, lease or easement, and
Enbridge complied with those terms and conditions, the ITS
specified that it would provide Enbridge a safe harbor from
ESA liability for incidentally taking those species within the
geographic scope of any area in which Enbridge was bound
to, and did, comply.

                   C. Procedural History

     Sierra Club filed suit against the Corps in August 2013,
on the day Enbridge began construction of Flanagan South.
The organization amended its complaint soon thereafter to
add new claims and name new federal-agency defendants.
The amended complaint asserted that NEPA analysis was
required in light of requested easements over federal lands,
Clean Water Act verifications, and the issuance of the ITS.
Sierra Club claimed that those actions, “individually and
collectively, constituted major federal action that triggered
defendants’ NEPA obligations” to prepare NEPA analysis of
“the entire Project.” Compl. ¶ 5. Sierra Club contended that
a “massive pipeline has been authorized . . . without any
NEPA review of the extensive environmental impacts of the
entire pipeline.” Id. ¶ 7.4 Sierra Club also asserted a Clean
4
  Sierra Club also alleged that the agencies failed to designate a
“lead agency,” preferably the Corps, to oversee the NEPA analysis.
Compl. ¶¶ 40, 187; see 40 C.F.R. § 1501.5(c).
                             20
Water Act claim against the Corps, alleging that the
verifications the Corps issued under Nationwide Permit 12
were unlawful because, as relevant here, the agency failed to
evaluate the pipeline’s cumulative impacts. Id. ¶ 192. Sierra
Club asserted its NEPA and Clean Water Act claims in
conjunction with the Administrative Procedure Act, seeking a
declaration that the alleged federal actions were all unlawful
and an order “enjoining Enbridge from conducting any
activities in reliance on” them.

     Sierra Club moved for a preliminary injunction, Enbridge
intervened as a defendant, and the district court denied
preliminary relief. Later, on cross-motions for summary
judgment, the district court ruled in favor of the defendants,
observing that the agencies had “permitting authority over
only small segments of this private pipeline project and none
of the defendant agencies, alone or in combination, ha[d]
authority to oversee or control the vast portions of the []
Pipeline that traverse private land.” Sierra Club v. Army
Corps of Eng’rs, 64 F. Supp. 3d 128, 133-34 (D.D.C. 2014).
The court also ruled against Sierra Club on its Clean Water
Act claim, holding that the Corps lawfully conducted region-
based analyses of the adverse cumulative effects of the water
crossings it verified under Nationwide Permit 12. Id. at 155-
57. On the same day that it entered summary judgment, the
district court entered a separate order denying Sierra Club’s
two pending motions to supplement and amend its first
amended complaint. Sierra Club timely appealed.

                       II. Mootness

     At the threshold, we must confirm our subject matter
jurisdiction. North Carolina v. Rice, 404 U.S. 244, 246
(1971). Enbridge contends that, as a prudential matter, we
should dismiss this appeal as moot because the agencies have
                              21
already granted the various authorizations at issue and
construction of the pipeline is now complete. In Enbridge’s
view, the court cannot now remedy any injuries that might
stem from the claimed NEPA violations because NEPA’s goal
of requiring the federal government to study and publicly
explain anticipated environmental effects before taking action
would not be furthered by post-construction NEPA review.
At this point, Enbridge argues, there is “no real opportunity
for any of the Defendants to reconsider their decisions,” and
“any further public comment could have no impact on the
Defendants’ decision-making, since the agencies could not
effectively act on the input provided.” Enbridge Br. 13, 16.
Enbridge likewise argues that Sierra Club’s Clean Water Act
claim is moot because “the minimal impacts to jurisdictional
waters under [Nationwide Permit 12] at stake in this litigation
have already occurred” and “[t]here are no ongoing
unmitigated impacts.” Id. at 16-17.

     This case is not moot because an order wholly or partly
enjoining operation of the pipeline, pending further analyses
of the pipeline’s environmental impact, would provide some
degree of “effectual relief.” See Church of Scientology of
Cal. v. United States, 506 U.S. 9, 12-13 (1992). “Even
though it is now too late to prevent or to provide a fully
satisfactory remedy for” the harms Sierra Club identifies, the
court has the “power to effectuate a partial remedy,” and that
“is sufficient to prevent this case from being moot.” Id. at 13.
“[T]his case presents a live controversy” because, were this
court to hold that the agencies’ NEPA analysis was
inadequate or their decisions otherwise arbitrary and
capricious, they “would have to correct the decision-making
process.”      Columbia Basin Land Protection Ass’n v.
Schlesinger, 643 F.2d 585, 591 n.1 (9th Cir. 1981). If the
NEPA analysis were legally inadequate, “we could order that
the [pipeline] be closed or impose restrictions on its use,” at
                              22
least on federally authorized segments, “until [the agencies]
complied with NEPA.” Airport Neighbors All., Inc. v. United
States, 90 F.3d 426, 429 (10th Cir. 1996).

    More extensive environmental analysis could lead the
agencies to different conclusions, with live remedial
implications.    If a broader NEPA analysis uncovered
additional environmental harms, the removal of the
challenged project, at least from certain areas, “could be
required.” Schlesinger, 643 F.2d at 591 n.1. Even assuming
claims “relating to the construction of” the pipeline were
moot, “we still may consider whether [the agencies] complied
with NEPA by adequately addressing the environmental
impacts resulting from the enhanced use of” it. Airport
Neighbors All., 90 F.3d at 429. The agencies could call for
additional mitigation and monitoring, or could decide not to
renew their respective authorizations. See, e.g., 33 C.F.R.
§ 330.5(d). There is no basis for Enbridge’s contentions that
none of the types of environmental effects that agencies must
investigate under NEPA could be avoided, undone, or more
robustly mitigated and monitored.

     This case is thus distinguishable from those in which the
court could not provide any of the relief sought. In Sierra
Club v. U.S. Army Corps of Engineers, for example,
environmental challenges to the Corps filling wetlands to
construct a sports complex were moot once the construction
was fully completed because it was undisputed that the
wetlands could not be restored, and the wetlands were the
only resource in which the plaintiffs claimed an interest. 277
F. App’x 170, 173 (3rd Cir. 2008). The completion of the
project and the limited nature of the plaintiffs’ asserted
interest in that case eliminated “the opportunity for any
meaningful relief to Plaintiffs’ alleged injuries.”         Id.
(emphasis added).
                              23
    This case presents a live controversy, and we reject
Enbridge’s suggestion that we dismiss the appeal for
prudential reasons.       That conclusion comports with
Congress’s objective in the various federal laws at issue here
that require environmental review and authorization in
advance. “If the fact that [projects] are built and operating
were enough to make [a] case nonjusticiable,” agencies and
private parties “could merely ignore the requirements of
NEPA” as well as other statutes requiring pre-construction
authorization or review, “build [their] structures before a case
gets to court, and then hide behind the mootness doctrine.”
Schlesinger, 643 F.2d at 591 n.1. But “[s]uch a result is not
acceptable.” Id.; see also West v. Sec’y of Dep’t of Transp.,
206 F.3d 920, 925 (9th Cir. 2000). We thus proceed to the
merits of Sierra Club’s challenge.

                          III. NEPA

     Sierra Club contends that the agencies should have
conducted NEPA review of the pipeline as a whole. The only
alleged federal action that, by its terms, addressed the entire
pipeline was the Service’s ITS in its Biological Opinion.
Sierra Club argues that either the Service’s issuance of the
ITS during Section 7 consultation with the Corps and Bureau,
or the Corps’s implementation of the ITS as a condition of the
Clean Water Act verifications it issued to Enbridge,
constituted federal action encompassing all of Flanagan
South, thereby mandating whole-pipeline NEPA review. The
Bureau also consulted with the Service in light of the
easements it was granting to Enbridge, but Sierra Club does
not invoke the Bureau or its easements in arguing that the ITS
triggered NEPA—perhaps because the easements, unlike the
Corps’s verifications, contained no explicit terms
implementing the ITS.
                              24
     We conclude, on the facts of this case, that the Service’s
issuance of the ITS was not, standing alone, federal action
triggering NEPA review.         By contrast, the Corps’s
implementation of the ITS as a condition of its Clean Water
Act verifications was federal action, but with geographic
scope far more limited than the NEPA review Sierra Club
seeks. In advocating for review of the entire pipeline, Sierra
Club unsuccessfully invokes the doctrine against
impermissible segmentation of NEPA review in an effort to
trigger NEPA’s connected- and cumulative-actions doctrines
and the Corps’s agency-specific NEPA regulations. Sierra
Club did not preserve a claim for NEPA analysis limited to
the verification and easement areas, so we have no occasion
to consider it. We must therefore reject Sierra Club’s NEPA
arguments on appeal.

     A. Implementation of the ITS as Federal Action

     An ITS, as explained above, is a set of terms and
conditions that the Service provides under Section 7 of the
ESA to other federal agencies planning actions likely to affect
listed species. In this case, Section 7 required the Corps and
the Bureau—action agencies—to consult with the Service and
the Service to render a Biological Opinion regarding the
Corps’s anticipated Clean Water Act verifications and the
Corps and the Bureau’s grants of easements. See 16 U.S.C.
§ 1536; 50 C.F.R. § 402.14. The Biological Opinion
examined the entire Flanagan South project and set forth in
the ITS measures to mitigate, monitor, and report take of
endangered species incident to the project. The Corps
implemented the ITS in its Clean Water Act verifications,
although only to a limited geographic extent. Compliance
with the ITS, insofar as action agencies made it binding and
enforceable, provided Enbridge with a safe harbor from ESA
liability.
                              25
     The Service’s development and issuance of the Section 7
ITS, standing alone, was not federal action. But, as explained
below, the Corps’s implementation of the ITS was federal
action, albeit of confined scope. An agency’s advice to
another agency on how that agency should proceed with its
permitting actions does not amount to federal action under
NEPA. The Service could, in a different context, be held to
be an “action agency” for NEPA purposes. See San Luis, 747
F.3d at 644 (explaining that, in Ramsey v. Kantor, 96 F.3d
434 (9th Cir. 1996), the National Marine Fisheries Service, a
consulting agency, also was an action agency when its
conduct was, in substance, identical to the process for issuing
a permit). But the record in this case makes clear that the Fish
and Wildlife Service acted only in its consultative role,
“merely offering its opinions and suggestions to [the Corps],
which, as the action agency, ultimately decides whether to
adopt or approve the [ITS].” Id. at 642. In that respect, the
Service and the Corps’s relationship here is analogous to that
between the Service and the U.S. Bureau of Reclamation in
San Luis, in which the Service had issued an ITS to
Reclamation regarding the effect of a major water works
project on the endangered Delta Smelt. See id. at 592. The
Service’s role in San Luis was to consult, and Reclamation
was the action agency implementing the ITS. Here, similarly,
it was the Corps’s action, by way of adopting and
incorporating the ITS in the verifications of Flanagan South’s
water crossings under the Clean Water Act, that qualified as
federal action under NEPA. See 40 C.F.R. § 1508.18(b).

     The Service was not obligated in San Luis or in this case
to complete a NEPA analysis, because an agency need not
complete such analysis “where another agency will authorize
or implement the action that triggers NEPA.” 747 F.3d at
644; accord Miccosukee Tribe of Indians of Fla. v. United
States, 430 F. Supp. 2d 1328, 1335 (S.D. Fla. 2006). This
                              26
case is thus unlike Ramsey, in which the National Marine
Fisheries Service issued a Biological Opinion and ITS and
was, under the particular circumstances of that case, also the
agency that authorized the species-taking action, thus making
the Service’s Section 7 ITS, standing alone, “functionally
equivalent to a permit.” 96 F.3d at 444; see also San Luis,
747 F.3d at 643-45 (distinguishing Ramsey on that basis).

     The defendants are only partly correct that the ITS in this
case was not the functional equivalent of a permit. Agency
Br. 44; Enbridge Br. 37, 39; see also Sierra Club, 64 F. Supp.
3d at 149-50 (drawing that conclusion). The Service’s
issuance of the ITS was not the functional equivalent of a
permit, but the Corps’s incorporation of the ITS was. When
the Service issues an ITS in its consultative role, Enbridge
correctly notes, it “do[es] not allow or authorize (formally
permit) incidental take under section 7.” Enbridge Br. 38
(quoting Section 7 Handbook, supra, at x). When the Service
issues a Section 10 permit directly to a private party, it
functions as an action agency. Before it began construction,
Enbridge considered applying to the Service for a private
Section 10 permit. Once the Service estimated that the
Section 10 process could “take years to complete,” Enbridge
decided against the Section 10 route. Enbridge instead opted
only to participate in the speedier Section 7 process and
settled for a much more limited authorization of anticipated
take. It was only when the Corps formally incorporated the
ITS into its Clean Water Act verifications that it gave
Enbridge permission to take species free from the threat of
ESA liability. The Corps-implemented ITS is the functional
equivalent of a permit and thus constitutes federal action
subject to NEPA. See 40 C.F.R. § 1508.18(b)(4). But
because its permission is limited to the areas subject to the
verifications, it is federal action of much more limited scope
                               27
than Sierra Club contends; contrary to Sierra Club’s claim, it
does not require NEPA review of the whole pipeline.

     The district court concluded that the Corps’s
incorporation of the ITS in its verifications did not trigger
NEPA because, the court reasoned, a verification is “not a
major federal action in and of itself” and thus cannot be
“transformed” into cognizable action on account of
incorporating an ITS. Sierra Club, 64 F. Supp. 3d at 149.
The court’s conclusion was based in part on the assumption
that the Corps had already made a “fully-informed decision to
authorize certain activities . . . ex ante under the nationwide
permitting system.” Id. at 147.            That assumption is
unfounded in this context, however: Nationwide Permit 12
and Corps regulations make clear that the Corps did not assess
effects on specific listed species when it authorized categories
of actions through promulgation of the general permit; rather,
it deferred any consideration of species impacts and
authorization of species take until the verification stage, in the
context of specific projects. See 33 C.F.R. § 330.4(f); 77 Fed.
Reg. at 10,187; App. 327 (Decision Document for Nationwide
Permit 12).

     The defendants contend that the ITS, even as
implemented by the Corps, did not constitute action triggering
NEPA because its requirements are “modest” and “limited to
monitoring.” Agency Br. 46. They note that, under the
regulations, “reasonable and prudent measures” that an ITS
requires “cannot significantly modify the proposed action.”
Id.; see 50 C.F.R. § 402.14(i)(2). The defendants thereby
seek to distinguish this case from those in which NEPA
analysis is triggered by ITS conditions that “substantially
modify” the action, Agency Br. 48, or “substantially alter the
status quo,” Enbridge Br. 43.
                              28
     The defendants fail their own test. The “status quo” is
not, as their argument assumes, a fully approved and
constructed Flanagan South pipeline; rather, the baseline
against which the significance of the federal action must be
measured is no pipeline approved and no species killed or
habitat disturbed. Authorizing take of endangered species in
connection with pipeline construction and operation across
jurisdictional waters, and doing so only on the conditions that
Enbridge take mitigating conservation measures and monitor
species impact for the anticipated useful life of the pipeline,
was regulatory approval amounting to significant federal
action requiring environmental review under NEPA. See 40
C.F.R. § 1508.18(b)(4); see also San Luis, 747 F.3d at 642-
45; cf. Tenn. Valley, 437 U.S. at 172-73 (reflecting that,
although “[i]t may seem curious to some that the survival of a
relatively small number of three-inch fish . . . would require
the permanent halting of a virtually completed dam for which
Congress has expended more than $100 million,” the plain
language of the ESA “require[d] precisely that result”).

               B. Limited Scope of the ITS

     The Corps’s implementation of the ITS through its Clean
Water Act verifications was federal action that required
NEPA review, but the NEPA obligations arising out of that
action extended only to the segments under the Corps’s
asserted Clean Water Act jurisdiction. The verifications
purported to enforce the ITS against Enbridge only with
respect to the water-crossing segments that the Corps verified
under Nationwide Permit 12; they did not purport to permit
any take of species (or authorize any other action, for that
matter) outside those segments along the rest of the pipeline.
Indeed, the Corps explicitly disclaimed that it would enforce
compliance with the ITS with respect to the pipeline as a
whole.
                              29
     The record contextualizes and confirms the geographic
limitation of the verifications’ implementation of the ITS.
The Corps, the Service, and Enbridge debated jurisdictional
issues in the course of their Section 7 consultation. The
Service and Enbridge sought a pipeline-wide ITS, while the
Corps emphatically disclaimed responsibility outside the
verification areas. Enbridge requested that the Corps consult
with the Service under Section 7 “on the entire pipeline route
instead of the areas tied to Corps jurisdiction/regulatory
control,” perhaps because it envisioned that would be
tantamount to a shortcut Section 10 process. App. 402-403;
see also App. 382. The Corps suggested that the Service
issue a Section 10 permit covering non-Corps areas, but the
Service responded that it could not do so because Enbridge
had chosen not to apply for a Section 10 permit. App. 403.
The Corps continued to maintain that it had authority over “a
very small percentage” of the pipeline and that it would “only
initiate Section 7 ESA consultation, as appropriate, for the
limited activities associated with this project that it has
sufficient control and responsibility to evaluate,” noting the
Service might “provide authorization for any take . . . outside
of the Corps permit area under Section 10.” Id.

     The fact that the Service’s Biological Opinion assessed
the entire Flanagan South project does not undermine our
holding concerning the limited scope of NEPA-triggering
implementation of the ITS via the verifications. The ITS
provided that “the Corps . . . must insure that the [ITS’s
measures] become binding conditions of any contract or
permit issued [to Enbridge] to carry out the proposed action
for the exemption in section 7(o)(2) to apply.” App. 296. It
further provided that the ITS’s safe harbor could lapse if the
Corps failed to “implement the terms and conditions” or
“require any contracted group to adhere to the terms and
                              30
conditions of the [ITS] through enforceable terms that are
added to the permit.” Id.

      The four regional Corps offices, in turn, issued
verifications defining the limited scope of the ITS’s “binding
conditions,” see id., by “authoriz[ing] [Enbridge’s] work . . .
conditional upon [Enbridge’s] compliance with the mandatory
terms and conditions associated with the incidental take that
may occur within the Corps delineated permit areas,” App.
176 (emphasis added); see App. 385, 421 (other verifications
with same language); see also App. 225-26 (biological
opinion delimiting the Corps’s jurisdictional areas as the
verified water crossings and the two easements). The
verifications reiterate that “[f]ailure to comply with the terms
and conditions [of the ITS] within the Corps permit areas
(i.e., separate and distant [sic: distinct] waterbody crossings,
where work is verified by the Corps under Nationwide Permit
Number 12), where take of the listed species occurs or
adverse effects to designated critical habitat occurs, would
constitute an unauthorized take, and it would also constitute
non-compliance with your Corps permit.”               App. 176
(emphasis added).        The verifications explicitly advised
Enbridge that the ITS does not constitute authorization for
Enbridge to take endangered species beyond the verified
crossings. In particular, “in order to legally take a listed
species,” the Corps emphasized that Enbridge “must have
separate authorization under the Endangered Species Act (e.g.
an ESA Section 10 permit, or a Biological Opinion [] under
ESA 7, with ‘incidental take’ provisions with which
[Enbridge] must comply).” Id.

     Sierra Club’s claim for whole-pipeline NEPA analysis
based solely on the ITS therefore fails because, per the terms
of the ITS and the verifications themselves, the Corps had not
bound Enbridge to comply with the ITS beyond those
                              31
segments of the pipeline subject to the Corps’s Clean Water
Act jurisdiction. Moreover, Enbridge did not obtain a Section
10 permit to take listed species on the balance of the pipeline
outside the scope of the ITS-implementing verifications.

     Given that NEPA-triggering federal action occurred with
regard to the segments of the pipeline subject to the
verifications by virtue of the ITS being incorporated with
respect to those sections, we need not separately consider
whether the Corps’s verification of the pipeline’s water
crossings under Nationwide Permit 12, standing alone, would
have required NEPA analysis.           Even assuming the
verifications, by themselves, did warrant NEPA analysis, the
verifications do no more than the ITS to extend the
geographic scope of the federal action; it remains limited to
the verified segments.

   C. Failure to Preserve NEPA Claims for Less Than
                 Whole-Pipeline Review

     Sierra Club has failed to preserve its claim that the
several easement actions, verifications and ITS, taken
together, amount to a single federal action that requires its
own NEPA analysis. We assume arguendo that the Corps’s
and Bureau’s discrete easement actions and verifications
incorporating the ITS were all component parts of the same
federal action, but Sierra Club has failed to preserve an
argument that the government was required to perform a
unified NEPA analysis on anything less than the entire
Flanagan South pipeline. As discussed below, Sierra Club
has consistently argued only that some agency should have
conducted a pipeline-wide NEPA assessment. In the district
court, Sierra Club’s contention that the easements,
verifications, and ITS should have been considered together
under NEPA was an intermediate step in its argument that
                                  32
there should have been one, coordinated NEPA review that
encompassed the balance of the pipeline—including sections
not otherwise subject to federal review or authorization.

     The district court record makes clear that whole-pipeline
review was the only theory of NEPA deficiency that Sierra
Club pursued. Sierra Club’s claim that the agencies were
required to assess the entire Flanagan South project underlay
all the NEPA claims in its complaint. See, e.g., Compl. ¶ 5
(objecting that the alleged actions “triggered Defendants’
NEPA obligations,” but “none of the Defendant agencies
prepared either an [EA] or an [EIS] for the entire Project
pursuant to NEPA”), ¶ 7 (“In short, . . . this massive pipeline
has been authorized . . . without any NEPA review of the
extensive environmental impacts of the entire pipeline . . . .”).
In seeking preliminary relief, Sierra Club argued that the crux
of its NEPA claims was that the federal government was
obligated to scope a NEPA analysis to the entire pipeline.5
The district court remarked in its preliminary injunction ruling
that the gravamen of Sierra Club’s NEPA claims was that the
agencies had a collective obligation to perform environmental

5
  In its briefing in support of its motion for a preliminary injunction,
Sierra Club contended that the “Flanagan South Pipeline is a major
federal action” and framed the agencies’ alleged NEPA violations
as stemming from a failure to assess the impacts of Flanagan South
as a whole. Mot. for Prelim. Inj., No. 1:13-cv-1239 KBJ (Sept. 4,
2013), ECF No. 14, at 13. Sierra Club repeatedly objected that no
agency had prepared NEPA analysis scoped to the “entire” project.
E.g., id. at 5, 8, 19-21, 28, 38; Pls. Reply (Sept. 23, 2013), ECF No.
34, at 1-2, 7-10, 19-21. At the preliminary injunction hearing, too,
Sierra Club underscored its position that “[t]he question is whether
any federal agency has to look at the entire oil pipeline in its
[NEPA analysis].” Tr. of Prelim. Inj. Hr’g (Sept. 27, 2013), ECF
No. 91, at 11; see also id. at 12 (“The law. . . requires an agency to
consider the entire [pipeline] . . . .”).
                                33
review of the entire pipeline. Sierra Club v. U.S. Army Corps
of Engineers, 990 F. Supp. 2d 9, 13 (D.D.C. 2013). Later,
aware of the court’s framing of its case, Sierra Club continued
at the summary judgment phase to press the same theory
exclusively.6

     We will not reverse the judgment of the district court
based on the argument, not advanced below, that an agency
unlawfully failed to perform NEPA analysis on sections of
Flanagan South short of the entire length of the pipeline. See,
e.g., Potter v. District of Columbia, 558 F.3d 542, 547 (D.C.
Cir. 2009) (limiting our review to “only those arguments that
were made in the district court, absent exceptional
circumstances”). That claim is forfeited. Therefore, the only
NEPA question preserved for our consideration is whether the
federal actions of verifying the Pipeline’s water crossings
under Nationwide Permit 12, incorporating the ITS, and
granting the easements to cross federal lands required NEPA
analysis of the entire Flanagan South pipeline.

D. Inapplicability of the Connected Actions, Cumulative
    Actions, and Corps-Specific NEPA Regulations

     In contending that the federal actions within the
verification and easement areas required the government also
to assess the rest of the pipeline under NEPA, Sierra Club
invokes the doctrines of “connected actions” and “cumulative
actions” delineated in the CEQ regulations. See 40 C.F.R.
§§ 1508.25(a)(1)-(2), 1508.7.7 It also invokes Corps-specific

6
 See, e.g., Pls. Mot. for Summ. J., No. 1:13-cv-1239 KBJ (Dec 9,
2013), ECF No. 61, at 2, 13, 15-16, 45; Pls. Reply (Jan. 27, 2014),
ECF No. 75, at 1, 3, 7.
7
 Those regulations dictate the appropriate scope of EAs as well as
EISs. See Del. Riverkeeper Network v. FERC, 753 F.3d 1304, 1314
                              34
NEPA scoping regulations. See 33 C.F.R. § 325 App. B.
None of those bases supports Sierra Club’s claim.

     1.     Connected Actions.       The connected actions
regulation, on which Sierra Club relies most heavily, does not
dictate that NEPA review encompass private activity outside
the scope of the sum of the geographically limited federal
actions. The regulation provides, as relevant here, that
“actions” must be analyzed together in the same assessment if
they “[a]utomatically trigger other actions which may require
environmental impact statements,” “[c]annot or will not
proceed unless other actions are taken previously or
simultaneously,” or if they are “interdependent parts of a
larger action and depend on the larger action for their
justification.” 40 C.F.R. § 1508.25(a)(1). The point of the
connected actions doctrine is to prevent the government from
“segment[ing]” its own “federal actions into separate projects
and thereby fail[ing] to address the true scope and impact of
the activities that should be under consideration.” Del.
Riverkeeper, 753 F.3d at 1313.

     Delaware Riverkeeper illustrates the connected actions
regulation’s anti-segmentation principle, and why it does not
accomplish all that Sierra Club asks of it. Under Delaware
Riverkeeper, an agency cannot segment NEPA review of
projects that are “connected, contemporaneous, closely
related, and interdependent,” when the entire project at issue
is subject to federal review. Id. at 1308. In this case, the oil
pipeline is undoubtedly a single “physically, functionally, and
financially connected” project, but one in which less than five
per cent is subject to federal review. See id. The Natural Gas
Act requirement that natural gas pipelines be pre-certified for

(D.C. Cir. 2014); Grand Canyon Trust, 290 F.3d at 346; Kern v.
U.S. Bureau of Land Mgmt., 284 F.3d 1062, 1076 (9th Cir. 2002).
                                 35
public convenience and necessity made the whole pipeline in
Delaware Riverkeeper the subject of major federal action
triggering NEPA. We held that FERC unlawfully segmented
the requisite NEPA analysis by reviewing in separate portions
a pipeline that “function[ed] together seamlessly.” Id. at
1307, 1311. Here, the project is an oil pipeline, however, so
not subject to any such overall pipeline precertification.8
Sierra Club argues, in effect, that applying the connected
actions regulation to the sum of other approvals Flanagan
South did require draws into NEPA review the balance of the
pipeline project that is not otherwise subject to agency action,
thus subjecting it to the connected actions doctrine to the
same extent as was the case in Delaware Riverkeeper. Sierra
Club adds a step that the regulation does not support: The
connected actions regulation requires agencies to review the
picture as a whole rather than conduct separate NEPA reviews
on pieces of an agency-action jigsaw puzzle; it does not add a
multitude of private pieces to the puzzle and so require review
of a much larger picture. That limitation is highlighted by the
connected actions rule’s lack of reference to private parties—
a reference present in the cumulative action regulation, which
directs agencies to consider the cumulative impact of action
by an “agency (Federal or non-Federal) or person.” Compare
40 C.F.R. § 1508.25(a)(1), with id. § 1508.7 (emphasis
added). Background, private action is expressly encompassed
in the cumulative action analysis in a way that it is not for
connected action.


8
  Pipelines transporting oil within the United States are not subject
to any general requirement of federal governmental evaluation and
approval. In that way, oil pipelines are less regulated than natural
gas pipelines, which must be supported by a certificate of public
convenience and necessity from the Federal Energy Regulatory
Commission before they may be built. 15 U.S.C. § 717f(c)(1)(A).
See Del. Riverkeeper, 753 F.3d at 1307-10.
                                36
     Sierra Club also invokes Karst Environmental Education
& Protection, Inc. v. EPA, 475 F.3d 1291, 1296 (D.C. Cir.
2007), for the proposition that full-project NEPA review is
required where federal agencies have substantial involvement
in a private project such that it would not have been
undertaken without the federal action. In Karst, we noted our
dictum in Macht v. Skinner, 916 F.2d 13, 19 (D.C. Cir. 1990),
approving of the Fourth Circuit’s approach in Maryland
Conservation Council v. Gilchrist, 808 F.2d 1039 (4th Cir.
1986), to the “federalization theory.” See Karst 475 F.3d at
1296-97 (citing Macht, 916 F.2d at 14, 19). We went on in
Karst, however, to observe that “we have no binding
precedent adopting the federalization theory,” and we did not
there apply it. 475 F.3d at 1297. Indeed, Macht, too, came
out the other way, undercutting Sierra Club’s argument. The
rail project in Macht was not subject to whole-project NEPA
analysis because federal agencies had regulatory control over
“only a negligible portion of the entire project.” 916 F.2d at
19. The same is true here.

     Sierra Club offers no persuasive explanation why the
portions of the pipeline outside the verification and easement
areas constitute “federal actions” and thus “should be under
consideration.” Del. Riverkeeper, 753 F.3d at 1313. Rather,
Sierra Club’s more modest claim at oral argument was that
Delaware Riverkeeper and the connected action regulation
require that “the federal actions in this case—the easements,
the other areas within federal jurisdiction—those are
connected” and so should have been analyzed together. Oral
Arg. Rec. at 7:33-40.9 That is the accurate statement of the


9
 See also Oral Arg. Rec. at 7:57-8:11 (similar concession by Sierra
Club, recognizing the same limited holding in Hammond v. Norton,
370 F. Supp. 2d 226 (D.D.C. 2005), upon which it also relies).
                              37
connected actions doctrine, but, as noted above, the claim
resting on it was not preserved.

     2. Cumulative Actions. The cumulative actions
regulation is no more helpful to Sierra Club. “Cumulative
actions” are those that must be assessed together because they
have “cumulatively significant impacts.” 40 C.F.R. §
1508.25(a)(2). A cumulative impact is that “which results
from the incremental impact of the action when added to other
past, present, and reasonably foreseeable future actions
regardless of what agency (Federal or non-Federal) or person
undertakes such other actions.” Id. § 1508.7. The cumulative
actions doctrine is not concerned with geographic
segmentation; if it were, it would be wholly redundant of the
connected actions doctrine. See Coal. on Sensible Transp.,
Inc. v. Dole, 826 F.2d 60, 70-71 (D.C. Cir. 1987). Instead, it
prevents agencies from ignoring the environmental effects of
other actions, without regard to whether their author was
federal, because those effects set the baseline state of affairs
and thus the context in which the significance of proposed
federal action must be evaluated. An agency deciding
whether to approve construction of a replacement airport, for
example, must consider the prospective impact of the airport’s
added noise in the context of noise from other sources—
including private sources not traceable to agency action. See
Grand Canyon Trust, 290 F.3d at 346. Sierra Club’s
argument is not, however, that the agencies’ NEPA analyses
ignored the environmental impacts of cumulative actions on
discrete swaths of the pipeline, but that they failed to analyze
the entire length of the pipeline. The cumulative actions
doctrine therefore does not advance Sierra Club’s case.

    3. Corps Regulations. Appendix B of the Corps’s
agency-specific NEPA scoping regulations provides that
when a party requires a Clean Water Act permit to conduct a
                              38
specific activity that is part of a larger project, the Corps’s
NEPA analysis should encompass not only the specific
activity, but also “those portions of the entire project over
which the [Corps] has sufficient control and responsibility.”
33 C.F.R. § 325 App. B(7)(b)(1); see also id. § 325 App.
B(7)(b)(2)-(3). Sierra Club asserts that the Corps had the
requisite control and responsibility over all of Flanagan
South, citing the Corps’s jurisdiction over the verified water
crossings and the easement areas. The agencies respond that
Appendix B is categorically inapplicable to verifications (or
easements). As they interpret the text, structure, and history
of the Corps’s Appendix B, it applies only to NEPA analysis
triggered by issuance of individual Clean Water Act permits,
as opposed to general permits and verifications thereunder.

     We owe deference to the Corps’s interpretation of its own
NEPA regulations, see, e.g., Bostick, 787 F.3d at 1054;
Kentuckians for the Commonwealth v. U.S. Army Corps of
Eng’rs, 746 F.3d 698, 708 n.3 (6th Cir. 2014), and conclude
that the Corps’s interpretation of its own NEPA-implementing
regulations in that regard is a permissible one, see Bostick,
787 F.3d at 1054; cf. Save Our Sonoran, Inc. v. Flowers, 408
F.3d 1113, 1121 (9th Cir. 2005) (consulting Appendix B for
scope review based on an individual permit). As the Tenth
Circuit has stated, “in adopting Appendix B, the Corps
indicated that [it] would not apply to nationwide permits (or
verifications of permit coverage),” as the “appendix was
apparently designed to guide Corps officials in evaluating
permit applications for individual projects.” Bostick, 787
F.3d at 1054.10

10
   We hold today only that the agencies were not required to
perform a pipeline-wide NEPA review; we do not opine on whether
an agency lawfully could have conducted such a review, had it so
chosen.
                              39
                    IV. Clean Water Act

     As detailed above, the Flanagan South pipeline makes
approximately 1,950 discrete crossings of waters subject to
the Clean Water Act, and those water crossings involved
dredge and fill activity that required Enbridge to obtain
authorization from the Corps of its compliance with the Act.
Enbridge sought and obtained that authorization in the form
of verifications issued by four regional offices of the Corps
pursuant to Nationwide Permit 12. Sierra Club argues that the
Corps regional offices’ assessments of the cumulative effects
of the water crossings verified under Nationwide Permit 12
were unlawfully narrow and conclusory. See 33 U.S.C. §
1344(e)(1); 33 C.F.R. §§ 330.1(e)(2), 330.6(a); 77 Fed. Reg.
at 10,287. We review Sierra Club’s Clean Water Act claim
de novo, Sierra Club v. Van Antwerp, 661 F.3d 1147, 1150
(D.C. Cir. 2011), and hold that it lacks merit.

     Sierra Club first faults the Corps for assessing cumulative
effects on a regional basis, as opposed to a pipeline-wide
basis. It relies on Nationwide Permit 12’s instruction that the
district engineer’s decision shall “include an evaluation of the
individual crossings . . . as well as the cumulative effects
caused by all of the crossings authorized by the [Nationwide
Permit].” 77 Fed. Reg. at 10,287 (emphasis added). That,
Sierra Club asserts, means regional Corps staff must assess
the water crossings across the entire pipeline. Sierra Club
ignores, however, Nationwide Permit 12’s explication that
“cumulative effects are evaluated on a regional basis” and that
“[c]umulative effects analysis may be done on a watershed
basis, or by using a different type of geographic area, such as
an ecoregion.” Id. at 10,264.

    Sierra Club also faults the Corps for what Sierra Club
sees as inadequately explained conclusions. It asserts that the
                               40
District Managers merely parroted the language of the statute
and the general permit at the end of each verification
memorandum: “The proposed activity would result in only
minor individual and cumulative adverse environmental
effects and would not be contrary to the public interest.” E.g.,
App. 449. Such bare incantations, Sierra Club contends,
provide no insight into how or on what basis the agency
reached its decision.

     As the district court recognized, however, the District
Managers’ conclusions were not unsupported boilerplate; they
were “made at the end of a lengthy memorandum explaining,
among other things, the details concerning the scope of the
proposed project in each respective district, the expected
effect of the project on [jurisdictional] waters . . . within that
district, and specific mitigation techniques to be employed in
response . . . .” 64 F. Supp. 3d at 157. In light of the
surrounding context, we conclude that the Corps’s cumulative
effects conclusions were adequately supported and reasoned.
See Snoqualmie, 683 F.3d at 1163.

           V. Motion to Supplement and Amend

     Sierra Club also appeals the district court’s order denying
the organization’s motions to supplement and amend its
complaint. The defendants assert that Sierra Club failed to
appeal that order, pointing out that Sierra Club’s notice of
appeal explicitly referred only to the district court’s summary
judgment order. The district court issued both orders
concurrently, however, and we are satisfied that Sierra Club’s
notice of appeal adequately expressed its intent to appeal both
orders. Further, the defendants suffer no prejudice from our
consideration of the order denying the motions to supplement
and amend. See, e.g., Martinez v. Bureau of Prisons, 444
F.3d 620, 623 (D.C. Cir. 2006).
                              41
     Reviewing the district court’s denial of the motions to
amend and supplement for an abuse of discretion, Hall v. CIA,
437 F.3d 94, 101 (D.C. Cir. 2006), we affirm the district court
for substantially the same reasons explained in the challenged
order. Sierra Club sought to add to its complaint allegations
meant chiefly to show that the agencies had taken actions that,
the agencies recognized, required NEPA review as to some
portions of the pipeline. Specifically, Sierra Club sought to
allege that the Corps and Bureau issued EAs for the easement
areas—developments Sierra Club believed confirmed the
ripeness of its NEPA claims and provided a stronger foothold
for its arguments that the agency actions effectively
federalized the entire pipeline. Sierra Club also sought to add
allegations that EPA had commented to the Corps in
December 2013 that the Corps’s NEPA analysis of the
Arkansas River easement was deficient because it failed to
assess the entire pipeline.

     The district court did not abuse its discretion in denying
Sierra Club’s motion as futile. As the court explained, its
summary judgment analysis assumed that the grants of the
federal easements were ripe federal actions triggering some
degree of NEPA review. App. 633-34; see also 64 F. Supp. at
133 n.1. The completion of those EAs did not affect the
NEPA inquiry before the court, which concerned only the
scope of the NEPA analysis Sierra Club claims was required,
not the intensiveness of that review. Sierra Club’s own
motion advised that the proposed newly styled claims and
new allegations did “not involve any new . . . legal arguments
that [were] not already before [the] court.” And the existing
claims concerned only the breadth, not depth, of the agencies’
NEPA analysis. See, e.g., Compl. ¶¶ 5, 7. The proposed
supplement and amendment would not, for instance, have
added a new claim that the agencies should have performed
EISs rather than EAs on account of the easements. The
                              42
district court never had occasion to opine on such a claim, nor
do we.

                          *   *    *

     For the reasons stated, we affirm the judgment of the
district court.

                                                   So ordered.
     BROWN, Circuit Judge, concurring in the judgment: This
is not a close case. As the district court aptly noted, three
basic facts decide it: “a private company is constructing the
[Flanagan South] pipeline largely on privately-owned land;
the federal agencies that have been consulted about aspects of
the pipeline project have control over only a small portion of
the land and waterways that the pipeline traverses; and no
statute authorizes the federal government to regulate or
oversee the construction of a domestic oil pipeline.” Sierra
Club v. U.S. Army Corps of Eng’rs, 64 F. Supp. 3d 128, 157
(D.D.C. 2014). NEPA requires agency environmental review
when the agency undertakes a major federal action defined as
an action that significantly affects the human environment and
is subject to federal control and responsibility. 42 U.S.C. §
4332(2)(C); 40 C.F.R. § 1508.18; see also Winnebago Tribe
of Neb. v. Ray, 621 F.2d 269, 273 (8th Cir. 1980) (“As for
federal involvement, the fact that part of the line will cross the
Winnebago Reservation does not suffice to turn this
essentially private action into federal action. . . . Thus we
conclude that the Corps did not have sufficient control and
responsibility to require it to study the entire project.”).
Little more ink needs to be spilled to conclude that — given
federal control over less than 20 miles of the 600-mile
pipeline — NEPA cannot compel federal review of the entire,
essentially private, pipeline.

     Sierra Club has put forward several claims, all of them a
variation on the theme that NEPA requires some federal
agency, if not all of them collectively, to review the entire
pipeline as a connected action. The likelihood of Sierra
Club’s success on the merits was briefed, argued, and
thoroughly considered by the district court when it dismissed
their motion for preliminary injunction. See Sierra Club v.
U.S. Army Corps of Eng’rs, 990 F. Supp. 2d 9, 44 (D.D.C.
                                 2
2013). After a second perusal when federal defendants 1 filed
motions to dismiss and both parties cross-motioned for
summary judgment, the district court again concluded that
“[p]laintiffs are wrong to insist that any federal agency had an
obligation under NEPA or any other statute to conduct an
environmental review of the impact of the entire FS Pipeline
. . . given that the Federal Defendants have permitting
authority over only small segments of this private pipeline
project and none of the defendant agencies, alone or in
combination, have authority to oversee or control the vast
portions of the FS pipeline that traverse private land.” Sierra
Club, 64 F. Supp. at 134.

     The majority opinion retreads this familiar ground but
with considerably more angst. This case is wholly removed
from the contexts of San Luis & Delta Mendota Water
Authority v. Jewell, 747 F.3d 581 (9th Cir. 2014), and
Ramsey v. Kantor, 96 F.3d 434 (1996) — cases the opinion
devotes several pages to distinguishing. See Maj. Op. 25-27.
Here, no instance of federal involvement (alone or
collectively) amounted to the “functional equivalent” of a
permit nor was this a circumstance in which one federal
agency was advising another. And no amount of artful
pleading can convert these minor federal engagements into a
“connected action” that subjects the 580 miles of private
pipeline to NEPA review. See Delaware Riverkeepers v.
FERC, 753 F.3d 1304 (D.C. Cir. 2014).

     While the majority ultimately arrives at the same
destination, its route is needlessly circuitous, creating the
1
  “Federal defendants” here refers collectively to the United States
Corps of Engineers, the Department of Transportation Pipeline and
Hazardous Materials Safety Administration, the Fish and Wildlife
Service, the Department of Interiors Bureau of Indian Affairs, and
the Environmental Protection Agency.
                              3
impression that Sierra Club’s challenges fail by a hairsbreadth
rather than a hectare. Because I favor the district court’s
direct approach, I concur only in the judgment.
