                     FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

NORTH IDAHO COMMUNITY ACTION                
NETWORK,
                Plaintiff-Appellant,
                 v.
UNITED STATES DEPARTMENT OF
TRANSPORTATION; MARY E.
PETERS,* U.S. Secretary of
Transportation; UNITED STATES
FEDERAL HIGHWAY ADMINISTRATION;                    No. 08-35283
THOMAS J. MADISON, JR.,**
Administrator, U.S. Federal                         D.C. No.
                                                2:05-CV-00273-EJL
Highway Administration; PETER
                                                     OPINION
HARTMAN,*** Division
Administrator, Idaho Division,
U.S. Federal Highway
Administration; EDWIN B. JOHNSON,
Field Operations Engineer, Idaho
Division, U.S. Federal Highway
Administration; UNITED STATES
FISH & WILDLIFE SERVICE; IDAHO
TRANSPORTATION DEPARTMENT;
                                            


   *Mary E. Peters is substituted for her predecessor, Norman Mineta, as
U.S. Secretary of Transportation, pursuant to Fed. R. App. P. 43(c)(2).
   **Thomas J. Madison, Jr., is substituted for his predecessor, Mary E.
Peters, as Administrator of the U.S. Federal Highway Administration, pur-
suant to Fed. R. App. P. 43(c)(2).
   ***Peter Hartman is substituted for his predecessor, Steve Mareno, as
Division Administrator, Idaho Division, U.S. Federal Highway Adminis-
tration, pursuant to Fed. R. App. P. 43(c)(2).

                                 14099
14100        NORTH IDAHO COMMUNITY ACTION v. DOT


PAMELA LOWE,**** Director, Idaho            
Transportation Department,                  
             Defendants-Appellees.
                                            
         Appeal from the United States District Court
                   for the District of Idaho
          Edward J. Lodge, District Judge, Presiding

                    Argued and Submitted
             August 25, 2008—Seattle, Washington

                       Filed October 6, 2008

   Before: Thomas G. Nelson, Michael Daly Hawkins, and
               Jay S. Bybee, Circuit Judges.

                        Per Curiam Opinion




   ****Pamela Lowe is substituted for her predecessor, David S. Ekern,
as Director, Idaho Transportation Department, pursuant to Fed. R. App. P.
43(c)(2).
         NORTH IDAHO COMMUNITY ACTION v. DOT   14103


                     COUNSEL

Matthew K. Bishop, Western Environmental Law Center,
Helena, Montana, for the plaintiff-appellant.
14104      NORTH IDAHO COMMUNITY ACTION v. DOT
Deborah A. Ferguson, Assistant United States Attorney,
Office of the United States Attorney for the District of Idaho,
Boise, Idaho, for appellee United States of America; Murray
D. Feldman, Holland & Hart, LLP, Boise, Idaho, for appellees
Idaho Transportation Department, et al.


                         OPINION

PER CURIAM:

   Plaintiff North Idaho Community Action Network
(“NICAN”) appeals the district court’s grant of summary
judgment in favor of defendants United States Department of
Transportation (the “DOT”), Federal Highway Administra-
tion, and Idaho Transportation Department (collectively, the
“Agencies”). NICAN challenges a proposed highway con-
struction project on a portion of U.S. Highway 95 located in
northern Idaho. NICAN claims that the Agencies violated the
National Environmental Policy Act (“NEPA”), 42 U.S.C.
§ 4321 et seq., and Section 4(f) of the Department of Trans-
portation Act, 49 U.S.C. § 303(c). We affirm in part, reverse
in part, and remand with instructions.

        FACTS AND PROCEDURAL HISTORY

   U.S. Highway 95 (“US-95”) currently runs through the
heart of downtown Sandpoint, Idaho, and is the only highway
that ties northern Idaho to southern Idaho. The proposed high-
way construction project (the “Project”) will improve US-95
in and around Sandpoint.

   The Project will be funded and constructed in four separate
phases. The first, second, and fourth phases involve widening
the existing highway to four lanes. The third phase involves
realigning an approximate two-mile stretch of US-95 to create
a byway that will route the highway to the east of Sandpoint
           NORTH IDAHO COMMUNITY ACTION v. DOT          14105
and remove through-traffic from the downtown Sandpoint
area. Because the Agencies deem the third phase to be the
most important phase of the Project, the Agencies have pro-
ceeded with that phase first.

   In September 1999, the Agencies approved a final environ-
mental impact statement (the “1999 EIS”) for the Project. In
May 2000, the Agencies issued a record of decision (the
“ROD”) for the Project. In the ROD, the Agencies selected
the “Sand Creek Byway” as the preferred alternative for the
third phase of the Project. As initially planned in the 1999
EIS, the Sand Creek Byway involved constructing two miles
of new two-lane highway along the east side of Sand Creek,
building a partial interchange/bridge structure over Sand
Creek and Bridge Street, and building a full diamond inter-
change at the junction of US-95 and State Highway 200.

   In April 2005, the Agencies released an environmental
assessment (the “2005 EA”) that included various changes to
the Project design described in the 1999 EIS. These changes
all relate to the third phase of the Project, the Sand Creek
Byway, and were made in response to input from various
members of the local community. The changes include traffic
design modifications—such as building additional off-ramps
and adding a third lane for safer merging—as well as aesthetic
improvements and mitigation measures—such as constructing
a pedestrian and bicycle pathway along Sand Creek and build-
ing three artificial habitat enhancement areas in Sand Creek.
The 2005 EA concluded that the changes to the Project design
would not have significant impacts beyond those already con-
sidered in the 1999 EIS. Based on this conclusion, the Agen-
cies issued a Finding of No Significant Impact (“FONSI”).

   In August 2006, the Agencies prepared an environmental
reevaluation (the “2006 Reevaluation”) covering the Project.
The 2006 Reevaluation set forth additional changes to the
Project design and assessed possible environmental effects of
those changes. The majority of the changes involve dredging
14106      NORTH IDAHO COMMUNITY ACTION v. DOT
Sand Creek and will result in the removal of approximately
17,035 cubic yards of material from Sand Creek. The 2006
Reevaluation concluded that there was no additional signifi-
cant impact and that neither a supplemental environmental
impact statement (“SEIS”) nor an environmental assessment
(“EA”) was required.

   In July 2005, after the Agencies released the 2005 EA and
issued its FONSI determination, but before the Agencies pre-
pared the 2006 Reevaluation, NICAN filed suit in the district
court challenging the Agencies’ approval of the Project. On
the parties’ cross-motions for summary judgment, the district
court granted summary judgment in favor of the Agencies and
against NICAN.

   NICAN moved for an injunction pending appeal, which the
district court denied. NICAN then sought and obtained an
injunction pending appeal from a motions panel of this court.
After oral argument in this expedited appeal, we lifted the
injunction and allowed construction of the Sand Creek Byway
to commence. This Opinion sets forth the explanation for our
decision.

                STANDARD OF REVIEW

   We review a district court’s grant of summary judgment de
novo. Nw. Ecosystem Alliance v. U.S. Fish & Wildlife Serv.,
475 F.3d 1136, 1140 (9th Cir. 2007). The Administrative Pro-
cedure Act (“APA”) provides authority for the court’s review
of decisions under NEPA and Section 4(f) of the Department
of Transportation Act, 49 U.S.C. § 303(c). See Pit River Tribe
v. U.S. Forest Serv., 469 F.3d 768, 778 (9th Cir. 2006);
Alaska Ctr. for the Env’t v. Armbrister, 131 F.3d 1285, 1288
(9th Cir. 1997). Under the APA, a reviewing court may set
aside agency actions that are “arbitrary, capricious, an abuse
of discretion, or otherwise not in accordance with law.” 5
U.S.C. § 706(2)(A). As this court recently explained:
            NORTH IDAHO COMMUNITY ACTION v. DOT           14107
     Review under the arbitrary and capricious standard
     is narrow, and we do not substitute our judgment for
     that of the agency. Rather we will reverse a decision
     as arbitrary and capricious only if the agency relied
     on factors Congress did not intend it to consider,
     entirely failed to consider an important aspect of the
     problem, or offered an explanation that runs counter
     to the evidence before the agency or is so implausi-
     ble that it could not be ascribed to a difference in
     view or the product of agency expertise.

Lands Council v. McNair, 537 F.3d 981, 987 (9th Cir. 2008)
(en banc) (internal quotations and citations omitted).

                        DISCUSSION

I.   NEPA

   “NEPA ‘is our basic national charter for protection of the
environment.’ ” Ctr. for Biological Diversity v. Nat’l High-
way Traffic Safety Admin., 538 F.3d 1172, 1185 (9th Cir.
2008). Although NEPA does not impose any substantive
requirements on federal agencies, it does impose procedural
requirements. See Lands Council, 537 F.3d at 1000. Through
these procedural requirements, NEPA seeks to make certain
that agencies “ ‘will have available, and will carefully con-
sider, detailed information concerning significant environ-
mental impacts,’ and ‘that the relevant information will be
made available to the larger [public] audience.’ ” Id. (quoting
Robertson v. Methow Valley Citizens Council, 490 U.S. 332,
349 (1989)).

   NICAN argues that the Agencies violated NEPA’s proce-
dural requirements by (a) failing to consider alternatives to
changes to the Project set forth in the 2005 EA, (b) failing to
disclose and assess in the 2005 EA the impacts of dredging
Sand Creek, (c) failing to consider a tunnel alternative for the
Project, (d) failing to consider the impacts the Project will
14108       NORTH IDAHO COMMUNITY ACTION v. DOT
have on historical properties, and (e) failing to prepare a sup-
plemental environmental impact statement. We address each
of these claims in turn.

  A.    Failure to Consider Alternatives

   NICAN argues that the Agencies violated NEPA by failing
to consider alternatives to the various changes to the Project
design set forth in the 2005 EA. We disagree.

   [1] NEPA requires the agencies to “study, develop, and
describe appropriate alternatives to recommended courses of
action in any proposal which involves unresolved conflicts
concerning alternative uses of available resources.” 42 U.S.C.
§ 4332(2)(E). This “alternatives provision” applies whether an
agency is preparing an environmental impact statement
(“EIS”) or an environmental assessment (“EA”), and requires
the agency to give full and meaningful consideration to all
reasonable alternatives. Native Ecosystems Council v. U.S.
Forest Serv., 428 F.3d 1233, 1245 (9th Cir. 2005). However,
“an agency’s obligation to consider alternatives under an EA
is a lesser one than under an EIS.” Id. at 1246. Thus, whereas
with an EIS, an agency is required to “[r]igorously explore
and objectively evaluate all reasonable alternatives,” see 40
C.F.R. § 1502.14(a), with an EA, an agency only is required
to include a brief discussion of reasonable alternatives. See 40
C.F.R. § 1508.9(b).

   NICAN does not dispute that the Agencies adequately
explored and evaluated reasonable alternatives to the Project
in preparing the 1999 EIS. NICAN also does not challenge
the Agencies’ selection, in the ROD, of the Sand Creek
Byway as the preferred alternative. Rather, NICAN argues
that the Agencies violated NEPA because they failed to con-
sider alternatives to the various changes to the Project design
set forth in the 2005 EA.

   [2] In the 2005 EA, the Agencies considered and briefly
discussed two alternatives: the Project with the changes pro-
           NORTH IDAHO COMMUNITY ACTION v. DOT            14109
posed in the 2005 EA, and the Project without the proposed
changes (i.e., proceeding with the Project as previously
described in the 1999 EIS). As discussed in Section I.E.
below, the changes to the Project proposed in the 2005 EA
will not result in significant environmental effects that were
not previously evaluated in the 1999 EIS. Under these circum-
stances, we hold that the Agencies fulfilled their obligations
under NEPA’s alternatives provision when they considered
and discussed only two alternatives in the 2005 EA. See
Native Ecosystems, 428 F.3d at 1245-49 (holding that the
agency complied with NEPA’s alternatives provision in pre-
paring an EA where the agency considered only two
alternatives—a no action alternative and a preferred alterna-
tive); 40 C.F.R. § 1508.9(b) (requiring only a brief discussion
of reasonable alternatives in an EA).

  B.   Failure to Disclose/Analyze Dredging

   NICAN argues that the Agencies violated NEPA by failing
to disclose and assess in the 2005 EA, or a supplemental EA,
the impacts of dredging Sand Creek. We disagree.

   Prior to issuance of the 2005 EA, there were internal dis-
cussions within the Agencies regarding the possible need for
the excavation or dredging of Sand Creek. There also was,
however, a good deal of uncertainty within the Agencies
about whether dredging would be required and, if so, the
extent of that dredging. For example, the initial application to
the Army Corps of Engineers indicated a belief that no dredg-
ing would be required. And shortly before the 2005 EA was
issued, hydraulics engineers were still examining at least three
dredging alternatives, and the design remained “subject to
change.”

   The Agencies could not adequately or meaningfully evalu-
ate the environmental impacts of any potential dredging until
they had more information, which depended at least in part on
ongoing discussions with the Army Corps of Engineers and
14110      NORTH IDAHO COMMUNITY ACTION v. DOT
the Clean Water Act permitting process. Once additional
information regarding the proposed dredging was available,
the Agencies performed the 2006 Reevaluation to analyze the
dredging and its projected impacts, and to determine whether
the new information required the preparation of a SEIS or a
supplemental EA. See Idaho Sporting Cong. Inc. v. Alexan-
der, 222 F.3d 562, 566 (9th Cir. 2000); Price Road Neighbor-
hood Ass’n v. U.S. Dep’t of Transp., 113 F.3d 1505, 1510 (9th
Cir. 1997); 23 C.F.R. § 771.129(a) (1988). The Agencies con-
cluded that the dredging would not have significant environ-
mental impacts beyond those already considered, and thus
that neither a SEIS nor a supplemental EA was required.

   The Agencies’ use of the reevaluation process is substan-
tially similar to that approved in Price Road, 113 F.3d at
1510, and we find no fault with the Agencies’ use of that pro-
cess here.

   In Price Road, a freeway project initially contemplated two
below-ground enclosed tunnels but was revised to include two
fully-directional loop ramps instead of the tunnels. Id. at
1507-08. The Agencies considered, in an environmental
reevaluation, the environmental effects of the changes and
determined there were no discernible differences in the level
of environmental impacts beyond those previously consid-
ered. Id. at 1508. The agency thus did not prepare an EA or
EIS for the changes. Id.

   [3] We noted that, while NEPA does not specifically
address how an agency should decide when changes require
a more formal EA or EIS, the Federal Highway Administra-
tion had specifically provided for reevaluations as a means to
determine whether or not the approved environmental docu-
ment remains valid. Id. at 1509-10 (citing 23 C.F.R.
§ 771.129(c)). We thus concluded that if the agency, after the
requisite “hard look” in a reevaluation, determines that the
new impacts will not be significant (or not significantly dif-
ferent from those already considered), then the agency is in
             NORTH IDAHO COMMUNITY ACTION v. DOT                    14111
full compliance with NEPA and is not required to conduct a
supplemental EA. Id. at 1510; see also Highway J Citizens
Group v. Mineta, 349 F.3d 938, 959-60 (7th Cir. 2003) (hold-
ing that when a “known issue came into sharper focus after
the formal environmental documents were issued,” it was not
improper to use internal reevaluation to analyze the issue).

   [4] In the present case, the Agencies took the requisite
“hard look” at the impacts of dredging Sand Creek in the
2006 Reevaluation, and determined that there were no new
impacts that were significantly different than those already
considered and that neither a SEIS nor a supplemental EA
was therefore required. We hold that the Agencies did not act
arbitrarily or capriciously in making those determinations, and
that they complied with NEPA in their evaluation of the pro-
posed dredging.1

  C.    Tunnel Alternative

   NICAN argues that the Agencies violated NEPA by failing
to consider a new tunnel alternative for the Project. Again, we
disagree.

   [5] Agencies have a continuing obligation to consider new
information that comes to light, even after the issuance of an
EIS. See 40 C.F.R. § 1502.9 (c)(1)(ii) (requiring the agency to
prepare supplements to either draft or final environmental
impact statements if “[t]here are significant new circum-
stances or information relevant to environmental concerns and
  1
   NICAN’s reliance on Idaho Sporting Cong., 222 F.3d at 566-67, is
misplaced. In that case, this court already had determined there were defi-
ciencies in the agency’s EA and EIS. Rather than issue a revised EA and
EIS to address those deficiencies, the agency improperly attempted to
address the deficiencies through issuance of a supplemental information
report (“SIR”). In contrast, in the present case, as in Price Road, the
reevaluation process was used not in an attempt to correct deficiencies in
an EA or EIS, but instead to make an ex-ante decision about the need for
a SEIS or supplemental EA.
14112      NORTH IDAHO COMMUNITY ACTION v. DOT
bearing on the proposed action or its impacts”); see also
Marsh v. Oregon Natural Res. Council, 490 U.S. 360, 373-74
(1989) (“[A]n agency need not supplement an EIS every time
new information comes to light after the EIS is finalized. . . .
On the other hand, . . . NEPA does require that agencies take
a ‘hard look’ at the environmental effects of their planned
action, even after a proposal has received initial approval.”);
Friends of the Clearwater v. Dombeck, 222 F.3d 552, 558
(9th Cir. 2000) (“When new information comes to light the
agency must consider it, evaluate it, and make a reasoned
determination whether it is of such significance as to require
[a supplemental EIS].”) (internal quotation marks and citation
omitted); Hughes River Watershed Conservancy v. Glickman,
81 F.3d 437, 444-45 (4th Cir. 1996) (holding that the agency
violated NEPA by failing to take a “hard look” at new infor-
mation regarding zebra mussel infestation).

   [6] This continuing obligation, however, extends only to
new information or circumstances regarding environmental
impacts that may not have been appreciated or considered
when the EIS was prepared. An agency is not required by
NEPA to consider new alternatives that come to light after
issuance of the EIS absent “substantial changes in the pro-
posed action relevant to environmental concerns,” or “signifi-
cant new circumstances or information relevant to
environmental concerns and bearing on the proposed action or
its impacts.” 40 C.F.R. § 1502.9 (c)(1); see 40 C.F.R.
§ 1502.14.

  [7] Here, the tunnel alternative is not new “information” or
a new “circumstance” regarding environmental impacts that
may not have been appreciated or considered when the 1999
EIS was prepared, and there is no substantial change in the
Project that is “relevant to environmental concerns.” Accord-
ingly, we hold that the Agencies did not violate NEPA by fail-
             NORTH IDAHO COMMUNITY ACTION v. DOT                    14113
ing to consider the tunnel alternative when it was brought to
their attention in 2006.2

  D.    Impacts to Historic Properties

   NICAN argues that the Agencies violated NEPA by: (1)
taking a “phased approach” to how the Project will impact
historic properties, and (2) failing to take a “hard look” at how
the construction and operation of the Project will impact the
Burlington Northern Railroad Depot (the “Depot”). We dis-
agree and hold that the Agencies fully complied with NEPA
on this issue.

   [8] NEPA requires federal agencies to consider the environ-
mental impact of major federal action. See San Carlos Apache
Tribe v. United States, 417 F.3d 1091, 1097 (9th Cir. 2005)
(citing 42 U.S.C. § 4332(2)(C)); see also Coliseum Square
Ass’n, Inc. v. Jackson, 465 F.3d 215, 223-25 (5th Cir. 2006).
NEPA has no independent requirement that an agency exam-
ine, separate and apart from any environmental impacts, the
impact that a federal action will have on historic properties.
NICAN’s reliance on NEPA regulations requiring consider-
ation of environmental impacts to support its historic-
property-impact argument is therefore misplaced.

   [9] Moreover, although an EIS is required to include “dis-
cussions” of “historic and cultural resources,” see 40 C.F.R.
§ 1502.16(g), the Agencies’ 1999 EIS complied with this
requirement. The 1999 EIS considered the impacts the Project
is anticipated to have on historic properties, primarily focus-
ing on the impacts of the Sand Creek Byway alternative ver-
  2
    Moreover, because the tunnel alternative was not raised and identified
until June 2006, well after the notice and comment periods for the 1999
EIS and the 2005 EA closed, any objection to the failure to consider that
alternative has been waived. See Dep’t of Transp. v. Pub. Citizen, 541
U.S. 752, 764-65 (2004) (holding that objections to the failure to consider
alternatives beyond those evaluated in the EA were forfeited by failure to
identify additional alternatives during notice and comment period).
14114        NORTH IDAHO COMMUNITY ACTION v. DOT
sus a through-town couplet alternative. The Agencies
ultimately chose the Sand Creek Byway alternative, in part
because the through-town couplet alternative potentially
would have impacted numerous historic sites, whereas the
Sand Creek Byway alternative only would potentially impact
the Depot and some underground sites.3

   The 1999 EIS recognized possible noise and vibration
impacts, noted general steps that would be taken to minimize
impacts, and indicated that additional surveys and mitigation
measures would be undertaken after selection of the preferred
route. The 2005 EA included a more detailed noise analysis
following testing and modeling, which concluded that there
were no significant adverse effects from the Project.4 The
2005 EA also described various mitigation procedures to pro-
tect the Depot from other construction activities, including the
changes to the Project and ongoing monitoring, developed in
consultation with the State Historic Preservation Officer
(“SHPO”).5

   [10] We hold that the broad overview in the 1999 EIS of
the Project’s impacts on historic properties, coupled with the
specific, detailed analysis of the impacts of the Sand Creek
Byway, and mitigation measures to minimize those impacts,
was more than sufficient to meet NEPA’s requirements in
relation to historic properties.6
  3
     These underground sites could be protected by simply preserving any-
thing unearthed off-site.
   4
     We defer to the Agencies’ interpretation of these data. Lands Council,
537 F.3d at 993-94.
   5
     In determining whether the potential construction effects would likely
be significant, the Agencies are permitted to take into account mitigation
measures which reduce the impact of construction. See Wetlands Action
Network v. U.S. Army Corps of Eng’rs, 222 F.3d 1105, 1121 (9th Cir.
2000).
   6
     The sufficiency of the Agencies’ analysis under Section 4(f) of the
Department of Transportation Act, 49 U.S.C. § 303(c), is discussed sepa-
rately in Section II.A. below.
           NORTH IDAHO COMMUNITY ACTION v. DOT            14115
  E.   Failure to Prepare a SEIS

   [11] An agency is not required to prepare a SEIS every
time new information comes to light. See Marsh, 490 U.S. at
373. Rather, a SEIS is required only if changes, new informa-
tion, or circumstances may result in significant environmental
impacts “in a manner not previously evaluated and consid-
ered.” Westlands Water Dist. v. Dep’t of Interior, 376 F.3d
853, 873 (9th Cir. 2004) (citation omitted). To assist the
agency in determining whether a SEIS is required, an agency
may prepare an environmental report (such as a reevaluation)
or an EA. See 23 C.F.R. §§ 771.119(a), 771.129, 771.130(c).

   [12] Here the agencies prepared both an EA and a reevalua-
tion. In these documents, the Agencies considered the changes
to the Project and the impacts of those changes. Although the
changes would have somewhat different impacts from those
previously analyzed in the 1999 EIS, the Agencies determined
that those impacts were not significant or adverse enough to
require a SEIS.

  NICAN argues that the Agencies acted arbitrarily and
capriciously by failing to prepare a SEIS regarding the
changes to the Project discussed in the 2005 EA and the 2006
Reevaluation. NICAN contends that a SEIS was required
because of impacts to wetlands, cumulatively significant
impacts, controversial or uncertain impacts, and adverse
impact on historic sites. See 40 C.F.R. § 1508.27(b) (discuss-
ing factors which should be considered in evaluating intensity
of impact). We disagree and hold that a SEIS was not
required.

   As modified, the Project affected only an additional 0.32
acres of wetlands, which was also mitigated by construction
of 1.1 acres of additional wetland area in a different location.
See Wetlands Action Network, 222 F.3d at 1121 (holding that
an agency can consider mitigation effects that minimize the
impacts of a project in determining the significance of the
14116      NORTH IDAHO COMMUNITY ACTION v. DOT
project’s environmental impact). Further, the changes to the
Project relating to the Depot were in response to requests by
the SHPO to mitigate and protect the Depot from adverse
effects, and were not adverse consequences in and of them-
selves. Cf. Enos v. Marsh, 769 F.2d 1263, 1373-74 (9th Cir.
1985) (holding that it was not arbitrary and capricious for the
agency to find no adverse effect on archeological sites when
that finding was consistent with the opinion of a SHPO).

   Moreover, the uncertainty and controversy relied on by
NICAN are not directed to the changes in the Project, but to
the Sand Creek Bypass alternative itself. That alternative was
discussed and evaluated in the 1999 EIS, and any challenge
to the selection of that alternative has been waived. Cf. Dep’t
of Transp., 541 U.S. at 764-65 (holding that objections to the
failure to consider alternatives beyond those evaluated in the
EA were forfeited by failure to identify additional alternatives
during notice and comment period).

   Finally, the Agencies sufficiently considered the cumula-
tive impacts of the Project. In the 1999 EIS, the Agencies dis-
cussed and analyzed the environmental impacts of the Project
as initially proposed. In the 2005 EA and 2006 Reevaluation,
the Agencies determined that the changes to the Project did
not significantly impact the environment in a way not previ-
ously considered. NICAN has pointed to nothing that con-
vinces us that these determinations by the Agencies were
inaccurate, let alone arbitrary or capricious.

   [13] We hold that the Agencies’ determination that the
changes to the Project would not significantly impact the
environment in a way not previously considered, and that a
SEIS therefore was not required, was not arbitrary or capri-
cious. See Marsh, 490 U.S. at 373-74; see also Westlands
Water Dist., 376 F.3d at 873.
            NORTH IDAHO COMMUNITY ACTION v. DOT            14117
II.    Alleged Violations of Section 4(f) of the Department
       of Transportation Act

   All federally funded highway projects must comply with
not only federal environmental protection laws, such as
NEPA, but also with historic preservation laws, including
Section 106 of the National Historic Preservation Act, 16
U.S.C. § 470f (“§ 106”), and Section 4(f) of the Department
of Transportation Act of 1966, 49 U.S.C. § 303(c) (“§ 4(f)”).

   Section 106 is a procedural statute that describes the pro-
cess by which a project’s impacts to historical sites are identi-
fied. It provides that before a federal agency may authorize
the expenditure of funds for a federal or federally assisted
project, the agency must first consider the effects of the proj-
ect on “any district, site, building, structure, or object that is
included in or eligible for inclusion in the National Register.”
16 U.S.C. § 470f.

   Section 4(f), in contrast, imposes a substantive mandate.
See 49 U.S.C. § 303(c). It allows a federal project “requiring
the use of land of an historic site” to be approved only if “(1)
there is no prudent and feasible alternative to using that land;
and (2) the program or project includes all possible planning
to minimize harm to the park, recreation area, wildlife and
waterfowl refuge, or historic site resulting from the use.” 49
U.S.C. § 303(c) (emphasis added).

   NICAN argues that the Agencies violated § 4(f) by (a) fail-
ing to survey, identify, and evaluate § 4(f) properties for all
four phases of the Project, and (b) determining that a § 4(f)
analysis was not required because the construction and opera-
tion of the Project would not result in “use” of the Depot. We
examine each of these claims in turn.

  A.    Failure to Evaluate § 4(f) Properties for all Four
        Phases of the Project

   NICAN argues that the Agencies violated § 4(f) by failing
to survey for, identify, and evaluate the impacts on historic
14118        NORTH IDAHO COMMUNITY ACTION v. DOT
properties for all four phases of the Project as required by
§ 106 and § 4(f).

   The Agencies concede that they have taken a phased
approach and have conducted a detailed § 106 identification
process and § 4(f) evaluation only with respect to the Sand
Creek Byway phase of the Project, and have not done so with
respect to the remaining three phases of the Project. Further,
the Agencies correctly point out that the regulations govern-
ing the § 106 process allow a phased approach to identifying
historic properties in some circumstances. See 36 C.F.R.
§ 800.4(b)(2); 36 C.F.R. § 800.8(a)(1).

   [14] However, § 4(f) and its regulations require that the
§ 4(f) evaluation be completed before an agency issues its
ROD. See 23 C.F.R. § 771.135(b) (“Any use of lands from a
section 4(f) property shall be evaluated early in the develop-
ment of the action when alternatives to the proposed action
are under study.”) (emphasis added); 23 C.F.R. § 771.135(i)
(2007) (stating that evaluation of alternatives to using § 4(f)
property should be presented in an EIS or EA); 23 C.F.R.
§ 771.135(l) (stating that if an EIS is required for a project,
the agency should conduct the § 4(f) analysis in the EIS or
ROD).7 And because the § 4(f) evaluation cannot occur until
after the § 106 identification process has been completed, the
§ 106 process necessarily must be complete by the time the
ROD is issued. See, e.g., 49 U.S.C. § 303(d)(2) (allowing the
Secretary to find § 4(f) de minimis impact only if that deter-
mination has been developed in the consultation process
required under § 106).

  The District of Columbia Circuit reached the same conclu-
  7
    These regulations were in effect at the time of the Agencies’ decision
in this case. They have been removed and replaced with similar ones as
of April 11, 2008. 23 C.F.R. § 774.9 (a) & (b) still provide that § 4(f)
properties must be evaluated early while alternatives are under study, and
that the § 4(f) approval should appear in the EIS or ROD.
              NORTH IDAHO COMMUNITY ACTION v. DOT                    14119
sion in a markedly similar case, Corridor H Alternatives, Inc.
v. Slater, 166 F.3d 368 (D.C. Cir. 1999). In Corrider H, the
agency approved a plan for building a lengthy highway corri-
dor, which was divided into fourteen segments. Id. at 371.
The EIS selected an alternative that required the agency to
identify historic properties in each segment in sequence and
provided that no work would proceed where the treatment of
historic properties had not been finalized. Id. The ROD,
approving the selected alternative, recognized that the § 4(f)
evaluation could not be conducted until the § 106 identifica-
tion process was completed. Id. at 371-72.

   The District of Columbia Circuit held that the agency was
required to complete the § 4(f) process for the entire corridor
project before issuing the ROD. See id. at 372-74 (citing 23
C.F.R. § 771.135); see also Valley Cmty. Pres. Comm’n v.
Mineta, 373 F.3d 1078, 1087-88 (10th Cir. 2004) (“Section
4(f) regulations clearly require the FHWA to make the requi-
site Section 4(f) evaluations prior to issuing an ROD approv-
ing a proposed construction project.”); Benton Franklin
Riverfront Trailway & Bridge Comm. v. Lewis, 701 F.2d 784,
788-89 (9th Cir. 1983) (criticizing agency for failing to com-
plete Section 4(f) analysis earlier).8

   [15] We hold, consistently with the District of Columbia
Circuit’s decision in Corrider H, that an agency is required to
complete the § 4(f) evaluation for the entire Project prior to
issuing its ROD.
  8
    The Agencies’ reliance on City of Alexandria v. Slater, 198 F.3d 862
(D.C. Cir. 1999), is misplaced. In Slater, the agency identified historic
properties along the entire project corridor, and documented its findings
in a Memorandum of Agreement and a § 4(f) evaluation; the agency
deferred only the determination of whether some ancillary construction
activities might also impact § 4(f) properties. Id. at 873. In contrast, here
the Agencies concede that they have conducted the § 106 identification
process and § 4(f) evaluation only as to the Sand Creek Byway phase of
the project, and have not conducted the necessary identification and evalu-
ation for the other phases of the Project.
14120      NORTH IDAHO COMMUNITY ACTION v. DOT
   [16] The Agencies concede that they have taken a phase-
by-phase approach, that they have not completed the § 4(f)
evaluation for the entire Project, and that they already have
issued the ROD. The Agencies have accordingly violated
§ 4(f). We therefore reverse the district court’s grant of sum-
mary judgment on this issue.

  B.    “Use” of the Depot

   In the 1999 EIS, the Agencies performed a § 4(f) evalua-
tion with respect to the Depot. The Agencies concluded that
there was no feasible and prudent alternative to the use of the
Depot and that the proposed action included all possible plan-
ning to minimize harm to the Depot, thus allowing the Project
to proceed. See 49 U.S.C. § 303(c)(1).

   NICAN does not challenge the Agencies’ § 4(f) evaluation
contained in the 1999 EIS. Instead, NICAN argues that the
Agencies acted arbitrarily and capriciously when they deter-
mined that modifications to the Project set forth in the 2005
EA will not “use” the Depot for purposes of § 4(f), and that
a formal § 4(f) evaluation was therefore not required in rela-
tion to those modifications.

   The modifications at issue came about as a result of the
Agencies’ agreement with the SHPO to perform certain
repairs and make certain improvements to the Depot. The
agreed-to repairs include removing the sandstone water table
course, replacing missing bricks, repointing all masonry
joints, and reconstructing a concrete curb and walkway at the
west side. The agreed-to improvements include paving the
Depot access road and parking areas, adding lighting to the
pedestrian parking area, and building a handicap access ramp
and brick pathway connecting the parking area to the Depot.
These “modifications” will not have an “adverse effect” on
the Depot, but are instead improvements that inure to the ben-
efit of the Depot. See 49 U.S.C. § 303(c), (d)(2). And,
although occurring on Depot property, these improvements do
              NORTH IDAHO COMMUNITY ACTION v. DOT                    14121
not “permanently incorporate[ ] [the land] into a transporta-
tion facility” to bring it within the parameters of § 4(f). See
23 C.F.R. § 771.135(p)(1) (2000);9 see also Laguna Green-
belt, Inc. v. U.S. Dept. of Transp., 42 F.3d 517, 533 (9th Cir.
1994) (holding that properties were not actually or construc-
tively used in a proposed project where the project would
not “substantially impair the current features, activities and
attributes” of parklands and bike paths). These improve-
ments do not, therefore, involve a “use” of the Depot property
under § 4(f). See 49 U.S.C. § 303(c), (d)(2); 23 C.F.R.
§ 771.135(p)(1) (2000).

   Other modifications to the Project—such as installing a
construction fence and mesh grating, and excavating a trench
—involve activities that are temporary and minor, that have
been approved by the SHPO, and from which the land will be
fully restored. These activities also do not, therefore, involve
a “use” of the Depot property under § 4(f). See 23 C.F.R.
§ 771.135(p)(7) (describing when a temporary occupancy is
so minimal it does not constitute a “use”).

   [17] We hold that the Agencies did not act arbitrarily or
capriciously in determining that the modifications to the Proj-
ect discussed in the 2005 EA would not “use” the Depot prop-
erty within the meaning of § 4(f).

III.   Remedy

   Although we conclude the Agencies violated § 4(f) by fail-
ing to conduct the § 4(f) evaluation for the entire Project prior
to issuing the ROD, we find it unnecessary to enjoin the entire
Project while the Agencies complete the necessary evaluation.
All parties agree that the § 4(f) evaluation has been completed
with respect to the Sand Creek Byway phase of the Project.
  9
    This was the regulation in effect at the time of the Agencies’ decision;
it has now been removed and repromulgated in substantially the same
form at 23 C.F.R. § 774.17 (2008).
14122        NORTH IDAHO COMMUNITY ACTION v. DOT
The Sand Creek Byway has independent viability, beginning
and ending at points on existing US-95, and the Sand Creek
Byway will accomplish many goals of the overall Project.

   [18] On the unique facts of this case, we conclude that the
scope of injunctive relief should be limited to precluding the
Agencies from commencing construction of the remaining
three phases of the Project until the § 4(f) evaluation has been
fully completed. See, e.g., Sierra Club v. Bosworth, 510 F.3d
1016, 1034 (9th Cir. 2007) (after noting that some projects
were already approved and in operational stages, limiting
injunctive relief to projects that were approved after initiation
of the lawsuit and giving the district court discretion to also
exclude some projects that were approved later but already at
or near completion); Nat’l Parks & Conservation Ass’n v.
Babbitt, 241 F.3d 722, 739 (9th Cir. 2001) (limiting the scope
of injunctive relief to two components of vessel management
plan). We therefore remand to the district court with instruc-
tions to enter an appropriate injunction in accordance with our
decision. See Nat’l Parks, 241 F.3d at 740.10

   AFFIRMED IN PART, REVERSED IN PART, AND
REMANDED WITH INSTRUCTIONS. Each party to bear
its own costs on appeal.




  10
    Nothing in this decision shall be deemed to preclude NICAN or any
other interested party from challenging the Agencies’ § 106 identification
process and § 4(f) evaluation, once completed, with respect to the remain-
ing phases of the Project.
