                  FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

SNOQUALMIE VALLEY PRESERVATION         
ALLIANCE,
                Plaintiff-Appellant,
                                              No. 11-35459
                v.
UNITED STATES ARMY CORPS OF                    D.C. No.
                                           2:10-cv-01108-JCC
ENGINEERS,
               Defendant-Appellee,             OPINION
PUGET SOUND ENERGY, INC.,
    Intervenor-Defendant-Appellee.
                                       
        Appeal from the United States District Court
          for the Western District of Washington
       John C. Coughenour, District Judge, Presiding

                  Argued and Submitted
             May 8, 2012—Seattle, Washington

                    Filed June 26, 2012

     Before: Michael Daly Hawkins, Jay S. Bybee, and
              Carlos T. Bea, Circuit Judges.

                    Per Curiam Opinion




                            7555
7558     SNOQUALMIE VALLEY PRESERVATION v. USACE




                       COUNSEL

Charles A. Klinge, Groen Stephens & Klinge LLP, Bellevue,
Washington, for the plaintiff-appellant.

J. David Gunter II, U.S. Department of Justice, Environment
& Natural Resources Division, for the defendant-appellee.
         SNOQUALMIE VALLEY PRESERVATION v. USACE          7559
Mark W. Schneider, Perkins Coie LLP, Seattle, Washington,
for defendant-intervenor/appellee.


                         OPINION

PER CURIAM:

   Puget Sound Energy (“PSE”) maintains and operates a
hydroelectric power plant at the 268-foot-high Snoqualmie
Falls in the state of Washington. The Snoqualmie River drains
a large watershed above the falls, and all of the water from
this area must pass through a single narrow channel before it
reaches the falls, creating a bottleneck during heavy rains.
This subjects the City of Snoqualmie, located just upstream of
the falls, to persistent and significant flooding.

   In the process of upgrading and modifying the plant, PSE
plans to lower the dam located in the channel above the falls
in order to mitigate these upstream flooding problems. PSE
has already obtained a license for the project from the Federal
Energy Regulatory Commission (“FERC”). Because the
upgrade involves discharging fill material into the waters of
the United States, which is prohibited under the Clean Water
Act (“CWA”) without a permit, PSE sought verification from
the U.S. Army Corps of Engineers (“Corps”) that it could pro-
ceed under a series of general nationwide permits (“NWPs”)
authorizing certain discharges, rather than applying to the
Corps for an individual permit. The Corps verified that it
could. Downstream property owners formed the Snoqualmie
Valley Preservation Alliance (“Alliance”) to challenge this
decision, which they contend will exacerbate flooding prob-
lems below the falls. The district court granted summary judg-
ment for the Corps. For the reasons explained below, we
affirm.

                               I

   In 1898, a hydroelectric power plant was first constructed
at the falls. PSE proposed an upgrade to the plant in 1991,
7560       SNOQUALMIE VALLEY PRESERVATION v. USACE
which FERC approved in a 2004 license after a lengthy study
published in a 1996 Environmental Impact Statement (“EIS”).
Both upstream and downstream flooding effects were evalu-
ated in the EIS. On judicial review, we upheld FERC’s deci-
sion. Snoqualmie Indian Tribe v. FERC, 545 F.3d 1207 (9th
Cir. 2008).

   Meanwhile, in 2004 the Corps completed a section 2051
flood control project and published a 1999 Environmental
Assessment (“EA”) which evaluated the upstream and down-
stream flooding effects of the project. Because the project
implemented slightly different changes related to the falls
than those initially planned under the FERC license, PSE
applied for an amendment to the license. Under the proposed
changes to the project, the existing dam would be lowered by
2 feet and lengthened by 37 feet to match the newly excavated
river bank. FERC prepared an EA concluding that the pro-
posed changes would have little effect on flood elevations,
and granted the amendment in 2009. Puget Sound Energy,
Inc., 127 FERC ¶ 62,174, ¶ 64,482, 2009 WL 1549353, at *10
(2009).

   Because completion of the project would involve both tem-
porary and permanent excavation and fill of wetlands, PSE
needed a permit under section 404 of the CWA, 33 U.S.C.
§ 1344. There are two types of section 404 permits: individual
permits that authorize specific activities on a case-by-case
basis, id. § 1344(a), and general permits that provide standing
authorization for all activities that fit the description in the
permit, id. § 1344(e). Individual permits are subject to the
requirements of the National Environmental Policy Act
(“NEPA”). 33 C.F.R. § 325.2(a)(4). A general nationwide
permit, on the other hand, must undergo that extensive pro-
cess at the time the permit is promulgated, rather than at the
time an applicant seeks to discharge fill material under such
  1
   Section 205 of the Flood Control Act of 1948 is codified at 33 U.S.C.
§ 701s.
           SNOQUALMIE VALLEY PRESERVATION v. USACE                7561
a permit. Id. § 330.5(b)(3). Project proponents may usually
“proceed with activities authorized by NWPs without notify-
ing the [Corps].” Id. § 330.1(e)(1). The Corps does, however,
allow permittees to request verification from the Corps that an
activity complies with the terms and conditions of a nation-
wide permit, and in some cases permittees are required do so
prior to beginning work under the permit. Id. § 330.6(a)(1).

   PSE submitted pre-construction notification of its plans to
the Corps and sought verification that its activities would be
covered under NWPs 33 and 39. In a Verification Letter and
accompanying Decision Document, both issued on May 19,
2009, the Corps determined that PSE’s activities fell within
the scope of three different nationwide permits. First, the
removal of the old dam and the construction of the new dam
were determined to fall within the scope of NWP 3(a), which
authorizes discharges for the replacement of a current struc-
ture, including minor deviations. See Reissuance of Nation-
wide Permits, 72 Fed. Reg. 11,092, 11,181 (Army Corps of
Eng’rs Mar. 12, 2007).2 Second, the temporary river diversion
for purposes of preparing the work areas was determined to
fall within the scope of NWP 33, which authorizes temporary
discharges for “necessary . . . construction activities.” See id.
at 11,187. Third, the modifications to the power plant intakes
and powerhouse structures were determined to fall within the
scope of NWP 39, which authorizes discharges for the “ex-
pansion of . . . attendant features that are necessary for the
use” of “commercial” and “institutional” buildings. See id. at
11,188. The Corps concluded that the project would have
minimal individual and cumulative impacts and that it com-
plied with all terms and conditions of NWPs 3, 33, and 39,
and imposed a series of special conditions.

  The Alliance filed this lawsuit challenging the Verification
  2
   The Corps originally published the nationwide permits in the Code of
Federal Regulations, but since 1996 it has published them in the Federal
Register.
7562     SNOQUALMIE VALLEY PRESERVATION v. USACE
Letter. The complaint asserts three causes of action: first, the
Corps violated the CWA by authorizing discharges under the
nationwide permits rather than requiring an individual permit;
second, the Corps violated NEPA by failing to prepare the EA
or an EIS required for individual permits; and third, the Corps
violated the Administrative Procedure Act (“APA”) because
its authorization of the discharges was arbitrary and capri-
cious or otherwise not in accordance with the law. PSE inter-
vened in the proceedings as a defendant. On cross-motions for
summary judgment, the district court granted summary judg-
ment in favor of the Corps and PSE. This appeal followed.

                               II

   The district court’s grant of summary judgment is reviewed
de novo. Alaska Ctr. for the Env’t v. West, 157 F.3d 680, 682
(9th Cir. 1998). Section 706 of the APA grants jurisdiction to
a reviewing court to “hold unlawful and set aside agency
action, findings, and conclusions found to be arbitrary, capri-
cious, an abuse of discretion, or otherwise not in accordance
with law.” 5 U.S.C. § 706(2)(A). Thus, a court may set aside
an agency decision that has “entirely failed to consider an
important aspect of the problem,” Butte Envtl. Council v. U.S.
Army Corps of Eng’rs, 620 F.3d 936, 945 (9th Cir. 2010)
(internal quotation marks omitted), or failed to articulate a
“rational connection between the facts found and the conclu-
sions made,” Nat’l Wildlife Fed’n v. U.S. Army Corps of
Eng’rs, 384 F.3d 1163, 1170 (9th Cir. 2004) (internal quota-
tion marks omitted). However, “[t]he scope of review under
the ‘arbitrary and capricious’ standard is narrow and a court
is not to substitute its judgment for that of the agency.” Motor
Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins. Co., 463
U.S. 29, 43 (1983).

                              III

                               A

  PSE raises an initial jurisdictional argument which the
Corps does not: whether this suit is an improper collateral
         SNOQUALMIE VALLEY PRESERVATION v. USACE          7563
attack against the FERC license and amendment. First, PSE
argues that the claims made here could, and therefore should,
have been raised during judicial review of the FERC license,
presumably Snoqualmie Indian Tribe, 545 F.3d 1207. Second,
citing California Save Our Streams Council, Inc. v. Yeutter,
887 F.2d 908, 911-12 (9th Cir. 1989), PSE argues that the
“practical effect” of a judgment against the Corps in this case
would be to “restrain the licensing procedures authorized by
FERC.”

   [1] With regard to the first argument, we note that the
instant claims against the Corps could not have been raised in
the challenge to the FERC license amendment because the
Corps had not yet verified that PSE could proceed via general
nationwide permits rather than applying for an individual per-
mit. PSE does not contend that the Corps had no role to play
in this project, or that obtaining a section 404 permit was an
unnecessary step. The Alliance could therefore not have
brought any of their present claims in the earlier lawsuit.

   [2] In support of its second argument, PSE points to the
remedies requested by the Alliance, which include requiring
the Corps to impose mitigation measures, such as rebuilding
the dam to its original height and canceling the plans to widen
the riverbank. PSE notes that such remedies would interfere
with activities specifically authorized by the FERC license.
While this is true, it does not follow that this action is an
improper collateral attack on the FERC license. If the Alli-
ance were to prevail, the remedy would be an injunction
against the Corps to instruct PSE to apply for an individual
permit and to perform a full NEPA analysis of the proposed
action. The resulting EIS or EA would have no effect on the
validity of FERC’s license. The sufficiency of the hypotheti-
cal EIS or EA and any additional mitigation measures sug-
gested by the Corps is not before us, nor was it before the
district court.
7564       SNOQUALMIE VALLEY PRESERVATION v. USACE
                                  B

  [3] The Alliance’s primary argument on appeal is that
hydropower projects may only be authorized if they fall under
NWP 17, the only nationwide permit which specifically refer-
ences hydropower projects. The text of that permit is as fol-
lows:

         17. Hydropower Projects. Discharges of dredged
      or fill material associated with hydropower projects
      having: (a) Less than 5000 kW of total generating
      capacity at existing reservoirs, where the project,
      including the fill, is licensed by the Federal Energy
      Regulatory Commission (FERC) under the Federal
      Power Act of 1920, as amended; or (b) a licensing
      exemption granted by the FERC pursuant to Section
      408 of the Energy Security Act of 1980 (16 U.S.C.
      2705 and 2708) and Section 30 of the Federal Power
      Act, as amended.

72 Fed. Reg. at 11,184.

   [4] The Alliance’s argument that hydropower projects can
only be authorized under this NWP, or otherwise must
undergo the individual permitting process, is not supported by
the regulation. NWP 17 affirmatively licenses hydropower
projects of less than 5000 kW of generating capacity.3 It is
silent concerning hydropower projects of more than 5000 kW
of generating capacity. As the district court found, “[a]lthough
NWP 17 is the only general permit specifically referencing
hydropower projects, no language contained therein prevents
the Corps from applying other permits to hydropower projects
that meet those other permits’ standards.” Snoqualmie Valley
Pres. Alliance v. U.S. Army Corps of Eng’rs, No. C10-1108,
2011 WL 1215605, at *3 (W.D. Wash. Mar. 30, 2011).
  3
   It is undisputed that the plant here has over 5000 kW of generating
capacity.
          SNOQUALMIE VALLEY PRESERVATION v. USACE            7565
   The Alliance argues that when the Corps rejected a 1991
proposal to expand NWP 17 to all hydropower plants, it
implicitly determined that all hydropower plants above 5000
kW of generating capacity will necessarily have more than
“minimal impacts” on the environment and thus must undergo
individual review. But this argument ignores the structure and
purpose of the nationwide permit system. Each nationwide
permit has to undergo the NEPA process when it is promul-
gated. This process ensures that any activity authorized under
that nationwide permit will have “minimal adverse environ-
mental effects.” 33 U.S.C. § 1344(e)(1).

   [5] In 1991, the Corps determined that hydropower plants
above 5000 kW of generating capacity should not automati-
cally be determined to have “minimal adverse environmental
effects” by virtue of being a hydropower plant above 5000
kW of generating capacity. See Final Rule for Nationwide
Permit Program Regulations and Issue, Reissue, and Modify
Nationwide Permits, 56 Fed. Reg. 59,110, 59,123 (Army
Corps of Eng’rs Nov. 22, 1991). This is not a determination
that all hydropower plants above 5000 kW of generating
capacity must go through the individual permit review pro-
cess. It simply means that these plants, if they are to qualify
at all, must qualify under one of the other nationwide permits.
If other nationwide permits apply to the proposed activity,
then the Corps has studied the activities falling under that pro-
posed nationwide permit and concluded that they will have
“minimal adverse environmental effects.”

   [6] It is not the case, as the Alliance implies, that the Corps
is using a shortcut to authorize a large hydropower project
that will involve large amounts of discharge into wetlands or
rivers. All nationwide permits must comply with general
terms and conditions, and many nationwide permits have their
own limiting principles. As relevant here, NWP 39 specifies
that authorized activities “must not cause the loss of greater
than ½-acre of non-tidal waters of the United States.” 72 Fed.
7566       SNOQUALMIE VALLEY PRESERVATION v. USACE
Reg. at 11,189.4 If a hydropower project meets these other
limiting conditions, the Corps need not require an individual
permit simply because the project’s generating capacity is
over 5000 kW.

   [7] Importantly, this interpretation is consistent with “[t]he
agency’s longstanding practice.” See Frankl v. HTH Corp.,
650 F.3d 1334, 1353 (9th Cir. 2011). The Corps articulated
this very position in a guidance document in 1992:

        12.Q. Can an applicant perform an activity under
      any applicable NWP, even though one may appear to
      be specific to his proposed activity . . . ?

        12.A. Although several NWPs may be applicable,
      an applicant can, at his choice, use any NWP for any
      activity that meets the terms and conditions of that
      NWP.

Army Corps of Eng’rs, Qs & As on Nationwide Permits 5-6
(1992), available at http://www.usace.army.mil/Portals/2/
docs/civilworks/nwp/1992qanda.pdf.5 Thus, not only is the
action taken in this case consistent with the regulation, but it
is also in line with agency practice over time. The Alliance’s
challenge fails.
  4
    The Project in this case was estimated to impact approximately 0.22
acres. The half-acre-loss limitation also applies to the use of NWP 3 in this
case. See 72 Fed. Reg. at 11,102 (“If . . . NWP [3] is used with an NWP
with a ½ acre limit, such as NWP 39, then the ½ acre limit would apply
to the single and complete project.”).
  5
    The Alliance objects that we should not defer to an informal guidance
document that has not undergone full APA review. This argument con-
fuses the issue of deference to a final rule (which is not at issue in this
case) with the question of whether an agency has consistently interpreted
its own regulations.
           SNOQUALMIE VALLEY PRESERVATION v. USACE                7567
                                 C

   The Alliance next argues that even if NWP 17 is not exclu-
sively applicable to hydropower projects, the Corps erred in
verifying that NWPs 3 and 39 authorize the project.6 The veri-
fication decision at issue here involves a determination that
the proposed activity falls within the parameters of the Corps’
regulations enacting the nationwide permits. We “must give
an agency’s interpretation of its own regulations controlling
weight unless it is plainly erroneous or inconsistent with the
regulation.” Miller v. Cal. Speedway Corp., 536 F.3d 1020,
1028 (9th Cir. 2008) (internal quotation marks omitted). The
Corps’ interpretation in this case is neither.

                                 1

  [8] NWP 3(a) authorizes discharges from

      [t]he repair, rehabilitation, or replacement of any
      previously authorized, currently serviceable, struc-
      ture, or fill, or of any currently serviceable structure
      or fill authorized by 33 CFR 330.3, provided that the
      structure or fill is not to be put to uses differing from
      those uses specified or contemplated for it in the
      original permit or the most recently authorized modi-
      fication. Minor deviations in the structure’s configu-
      ration or filled area, including those due to changes
      in materials, construction techniques, or current con-
      struction codes or safety standards that are necessary
      to make the repair, rehabilitation, or replacement are
      authorized.

72 Fed. Reg. at 11,181. The Corps found that NWP 3 autho-
rized the removal of the old dam and the construction of the
new dam at a lower height.
  6
   The Alliance does not challenge the use of NWP 33, which the Corps
also found applicable to the project.
7568       SNOQUALMIE VALLEY PRESERVATION v. USACE
   [9] This is consistent with the regulation. The old dam is
to be “replace[d]” by a new one, and the new structure “is not
to be put to uses differing from those uses specified or con-
templated for it” originally. That is, the new dam will serve
the same purpose as the old dam in the hydropower project;
the modifications are meant to ensure better flood control
above Snoqualmie Falls. The “[m]inor deviations in the struc-
ture’s configuration” involve lowering the dam by approxi-
mately 11% and lengthening it by approximately 17%.7
Although the deviations are not precisely meant to bring the
project up to date with “current construction codes or safety
standards,” language in the regulatory history suggests that a
general “public safety” rationale suffices to bring a replace-
ment project with minor deviations under this nationwide per-
mit. See 56 Fed. Reg. at 59,120 (“[I]t is important to note that
. . . concerns for public safety warrant minor deviations for
repair and replacement activities.”). Protecting the upper val-
ley from excessive flooding rationally qualifies as a “public
safety” concern.

                                 2

   [10] Similarly, both the record and the text of the regula-
tion support the Corps’ conclusion that the modifications to
the power plant intakes and powerhouse structures fall within
the scope of NWP 39. That permit authorizes

      [d]ischarges of dredged or fill material into non-tidal
      waters of the United States for the construction or
      expansion of commercial and institutional building
      foundations and building pads and attendant features
      that are necessary for the use and maintenance of the
      structures. Attendant features may include, but are
      not limited to, roads, parking lots, garages, yards,
      utility lines, storm water management facilities, and
  7
   The 18.5-foot-high and 220-foot-long dam will be lowered by 2 feet
and lengthened by 37 feet.
          SNOQUALMIE VALLEY PRESERVATION v. USACE                7569
    recreation facilities such as playgrounds and playing
    fields. Examples of commercial developments
    include retail stores, industrial facilities, restaurants,
    business parks, and shopping centers. Examples of
    institutional developments include schools, fire sta-
    tions, government office buildings, judicial build-
    ings, public works buildings, libraries, hospitals, and
    places of worship. The construction of new golf
    courses, new ski areas, or oil and gas wells is not
    authorized by this NWP.

72 Fed. Reg. at 11,188-89. The project here involves the con-
struction of “attendant features that are necessary for the use
and maintenance” of the plant. The attendant features are
power plant intakes, tailraces, and powerhouses. As described
by PSE, this construction is necessary for the improved opera-
tion of the hydropower plant.

   [11] The Alliance objects that “commercial and institution-
al” structures are limited by the regulation to “stores and
buildings,” not hydropower projects. This argument fails
because the regulation specifically lists “industrial facilities”
as an example of “commercial developments.” A hydropower
plant is plainly an industrial facility. The Alliance’s only
argument to the contrary relies on its erroneous interpretation
of NWP 17. Deferring as we must to the agency’s interpreta-
tion and application of its own regulations, we conclude that
the Corps’ decision in this case is consistent with its regula-
tion.

                                D

    The Alliance objects that the Corps’ Verification Letter
does not contain a sufficient articulation of the basis for its
decision. This objection takes two forms. First, the Alliance
contends that the Corps’ analysis of NWPs 3 and 39 was not
articulated in the administrative record, and instead is a mere
litigation position. Second, the Alliance challenges the Corps’
7570     SNOQUALMIE VALLEY PRESERVATION v. USACE
determination that the project would comply with all applica-
ble general conditions, arguing that the Corps’ conclusory
statement that the “[p]roject complies with all terms and con-
ditions of the NWP 3, 33, and 39” is insufficient to pass APA
review.

   [12] It is true that “the agency must articulate a rational
connection between the facts found and the conclusions
made.” Nat’l Wildlife Fed’n, 384 F.3d at 1170 (internal quota-
tion marks omitted). The reviewing court “ ‘may not supply
a reasoned basis for the agency’s action that the agency itself
has not given.’ ” State Farm, 463 U.S. at 43 (quoting SEC v.
Chenery Corp., 332 U.S. 194, 196 (1947)). However, “a court
is not to substitute its judgment for that of the agency, and
should uphold a decision of less than ideal clarity if the agen-
cy’s path may reasonably be discerned.” FCC v. Fox Televi-
sion Stations, Inc., 556 U.S. 502, 513 (2009) (citation
omitted) (internal quotation marks omitted).

   [13] The Verification Letter at issue here does state rea-
sons for the action taken: the agency verified that PSE could
proceed under section 404 of the CWA because the project
had minimal individual and cumulative impacts and it com-
plied with all terms and conditions of NWPs 3, 33, and 39.
This conclusion is amply supported by facts in the administra-
tive record. To require more would be contrary to the regula-
tory scheme, which devised the system of general nationwide
permits to streamline the process, reduce redundancy, and
conserve agency resources. 33 C.F.R. § 330.1(b)
(“Nationwide permits . . . are designed to regulate with little,
if any, delay or paperwork certain activities having minimal
impacts.”); see also Crutchfield v. Cnty. of Hanover, Va., 325
F.3d 211, 215 (4th Cir. 2003) (“NWP verification is much
simpler than the individual permit process.”). The purpose of
this scheme is to enable the Corps to quickly reach determina-
tions regarding activities that will have minimal environmen-
tal impacts, such as those involving the discharge of less than
a half an acre of fill. Requiring an elaborate analysis of the
          SNOQUALMIE VALLEY PRESERVATION v. USACE           7571
applicable regulations and the facts would defeat this purpose.
See Orleans Audubon Soc’y v. Lee, 742 F.2d 901, 909-10 (5th
Cir. 1984).

   Moreover, a permittee is usually not required to notify the
Corps in the first place that it is proceeding under a nation-
wide permit, except where the applicable nationwide permit
specifically so notes. See, e.g., 72 Fed. Reg. at 11,181 (specif-
ically noting that NWP 3(b) requires pre-construction notifi-
cation, but not requiring notice for activities under the rest of
NWP 3, such as 3(a)). And even where pre-construction noti-
fication is required, a permittee is not required in most cases
to supply the Corps with information about how the project
will satisfy each general condition. Where there are excep-
tions to this practice, they are explicitly noted. Id. at 11,195
(requiring “documentation demonstrating compliance with the
Endangered Species Act” and “documentation demonstrating
compliance with . . . the National Historic Preservation Act”).

   [14] Here, NWPs 33 and 39 require pre-construction noti-
fication. Id. at 11,187-89. PSE accordingly notified the Corps
of its project and requested verification. But the general con-
ditions that the Alliance alleges should have been evaluated
by the Corps do not place a burden of providing documenta-
tion on PSE. Without such documentation, it would be an
absurd result to require the Corps to evaluate and explain how
PSE will comply with these conditions. Indeed, as part of its
decision, the Corps actually reserved its determination of
whether the project will comply with all general and special
conditions: “In order for this NWP authorization to be valid,
you must ensure that the work is performed in accordance
with the enclosed Nationwide Permits 3, 33, and 39 Terms
and Conditions and the following special conditions.” The
nationwide permit system is designed to streamline the per-
mitting process. We decline to impose a new requirement of
a full and thorough analysis of each general condition based
on documentation the Corps may or may not have.
7572      SNOQUALMIE VALLEY PRESERVATION v. USACE
                                E

   [15] The Alliance bases its NEPA claim on the argument
that the Corps was required by the CWA to inform PSE that
it could not proceed under general nationwide permits, but
instead must apply for an individual permit. However,
because the Corps did not violate the CWA, it also did not
violate NEPA. Verifying that permittees may properly pro-
ceed under a nationwide permit does not require a full NEPA
analysis at the time of the verification.

                                IV

   Although the Corps’ analysis in this case is brief, it is suffi-
cient to pass judicial review. The Corps’ interpretation of its
own regulations is entitled to deference, and we affirm the
district court’s decision.

  AFFIRMED.
