                  FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


SIERRA CLUB; FRIENDS OF            Nos. 14-15998
THE WEST SHORE,                         14-16513
      Plaintiffs-Appellants,
                                       D.C. No.
             v.                2:13-cv-00267-JAM-EFB

TAHOE REGIONAL
PLANNING AGENCY,                      OPINION
      Defendant-Appellee.


      Appeal from the United States District Court
          for the Eastern District of California
       John A. Mendez, District Judge, Presiding

          Argued and Submitted April 12, 2016
               San Francisco, California

                  Filed November 2, 2016

    Before: J. Clifford Wallace, Mary M. Schroeder,
         and N. Randy Smith, Circuit Judges.

              Opinion by Judge Schroeder
2                     SIERRA CLUB V. TRPA

                            SUMMARY*


                       Environmental Law

    The panel affirmed the district court’s summary judgment
and award of costs in favor of Tahoe Regional Planning
Agency, a bi-state land use and environmental resource
planning agency for the Lake Tahoe Region, on
environmental organizations’ claims that the environmental
impact statement for TRPA’s Regional Plan Update did not
comply with the requirements of the Regional Planning
Compact between California and Nevada.

    The panel held that plaintiffs had standing and their
claims were ripe. Applying a standard similar to the standard
for evaluating an environmental impact statement under the
National Environmental Policy Act, the panel held that
TRPA’s environmental impact statement and Regional Plan
Update adequately addressed the localized effects of the
runoff created by the amount of development permitted under
the Update. TRPA’s analysis of the effects of concentrating
development in “community centers” was not arbitrary or
capricious and did not violate Compact article VII(a)(2)(A)
by failing to address significant environmental impacts of the
Regional Plan Update. The panel also held that TRPA’s
assumptions regarding best management practices and
whether they would reduce water quality impacts of
concentrated development under the Regional Plan Update
were not arbitrary or capricious and were supported by


    *
      This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                  SIERRA CLUB V. TRPA                      3

substantial evidence. The panel affirmed the district court’s
award of costs.


                        COUNSEL

Trent W. Orr (argued) and Wendy S. Park, Earthjustice, San
Francisco, California, for Plaintiffs-Appellants.

Whitman F. Manley (argued) and Howard F. Wilkins III,
Remy Moose Manley LLP, Sacramento, California; John L.
Marshall, Tahoe Regional Planning Agency, Stateline,
Nevada; for Defendant-Appellee.

Kamala D. Harris, Attorney General; Daniel L. Siegel,
Supervising Deputy Attorney General; Nicole U. Rinke,
Deputy Attorney General; Sacramento, California; for
Amicus Curiae California Resources Agency.

Cassandra P. Joseph, Senior Deputy Attorney General; Office
of the Attorney General, Carson City, Nevada; for Amicus
Curiae Nevada Department of Conservation and Natural
Resources.

Thomas Watson, City Attorney; Nira Doherty, Assistant City
Attorney; City of South Lake Tahoe, South Lake Tahoe,
Nevada; for Amici Curiae City of South Lake Tahoe,
California; El Dorado County, California; Placer County,
California; Douglas County; Nevada; Carson City and
County, Nevada; and Washoe County, Nevada.

Lewis S. Feldman and Kara L. Thiel, Feldman McLaughlin
Thiel LLP, Zephyr Cove, Nevada, for Amici Curiae Lake
Tahoe Community College, South Shore Chamber of
4                  SIERRA CLUB V. TRPA

Commerce, North Lake Tahoe Chamber of Commerce, Sierra
Nevada Association of Realtors, Incline Village Board of
Realtors, Lake Tahoe Visitors Authority, Tahoe Douglas
Visitors Authority, South Tahoe Alliance of Resorts, and
Barton Health.


                          OPINION

SCHROEDER, Circuit Judge:

                     INTRODUCTION

    The Lake Tahoe Region is an area of unmatched beauty
surrounding the largest alpine lake in North America. It first
caught the world’s attention with the 1960 Winter Olympics
at Squaw Valley, when the area became a recreation
destination and home to a rapidly expanding population. It
has since become the focus not only of admiration for the
lake’s beauty and clarity, but of litigation over the efforts to
preserve them. See, e.g., Suitum v. Tahoe Reg’l Planning
Agency, 520 U.S. 725 (1997); People v. Tahoe Reg’l
Planning Agency, 766 F.2d 1308, 1310 (9th Cir. 1985); Sierra
Club v. Tahoe Reg’l Planning Agency, 916 F. Supp. 2d 1098,
1105 (E.D. Cal. 2013).

    This case concerns the Regional Plan Update (“RPU”)
that the Tahoe Regional Planning Agency (“TRPA”) adopted
in 2012 after more than ten years of work. Plaintiffs, The
Sierra Club and Friends of the West Shore, are
environmentalist organizations that challenged the
environmental impact statement (“EIS”) for the RPU. They
now appeal the district court’s summary judgment in favor of
TRPA.
                    SIERRA CLUB V. TRPA                        5

    The RPU generally restricts future development to areas
that are already developed, and sets forth the amount of
further development that will be permitted in those areas in
the future. The precise nature of that development is to be
determined in Area Plans to be adopted later.

    Plaintiffs’ principal contentions in this appeal are that the
RPU fails adequately to address the localized effects of the
runoff created by the amount of development permitted, and
that the RPU improperly assumes that best management
practices (“BMP”s) can be utilized to achieve the planning
goals, in light of TRPA’s poor record of enforcing BMPs in
the past.

    We also must consider TRPA’s challenge to standing and
ripeness. While there will doubtless be more litigation
concerning subsequent Area Plans, Plaintiffs’ interests in the
lake are affected by the RPU, and they will have no future
opportunity to challenge the policies the RPU adopts. We
therefore hold that Plaintiffs have standing to assert claims
that are ripe.

    On the merits, however, we conclude that the district
court properly entered summary judgment in favor of TRPA.
The draft EIS drew criticisms that necessitated substantial
revisions, but the final EIS for the RPU adequately addressed
localized impacts on soil conservation and water quality.
Notably, while California had strenuously objected to certain
aspects of the draft EIS, particularly with respect to the
localized impacts of runoff, both California and Nevada now
urge approval of the plan, as evaluated in the final EIS. We
also hold that TRPA reasonably concluded that, in light of
anticipated improvements in BMP maintenance, the
6                   SIERRA CLUB V. TRPA

development permitted in the RPU would have less than a
significant effect on water quality.

    Our analysis must take place against the background of
past efforts to maintain the pristine quality of the lake, so we
begin with an historical summary.

    HISTORICAL BACKGROUND OF TRPA’S 2012
           REGIONAL PLAN UPDATE

    Lake Tahoe is located in the northern Sierra Nevada
Mountains, and covers 191 square miles. The Lake Tahoe
Region comprises 501 square miles, including the lake. The
Region encompasses the Lake Tahoe basin, a watershed
situated between the main crest of the Sierra Nevada and the
Carson mountain ranges. The lake’s outlet is the Truckee
River, running from the north end of Lake Tahoe to Pyramid
Lake in Nevada. The basin was acquired by the United States
in the mid-1800s, but later in the century, private owners
acquired much of the land and converted it to agricultural use,
as well as beginning the resort industry at the south end of the
lake. See Richard J. Fink, Public Land Acquisition for
Environmental Protection: Structuring a Program for the
Lake Tahoe Basin, 18 Ecology L.Q. 485, 493, 498–99 (1991).

    Two-thirds of the region is in California and one-third is
in Nevada. In the late twentieth century, the population of the
region expanded by more than 70%, with the most rapid
expansion, as described in the draft EIS, occurring in the
1970s.

    The attraction is the lake’s size, depth, and distinctive
blue color. The lake’s clarity is the result of the lack of algae.
See League to Save Lake Tahoe v. Tahoe Reg’l Planning
                   SIERRA CLUB V. TRPA                        7

Agency, 739 F. Supp. 2d 1260, 1264 (E.D. Cal. 2010), aff’d
in part & vacated in part, 469 F. App’x 621 (9th Cir. 2012).
In the region’s natural state, its poorly developed soils
contribute relatively small amounts of sediment to the lake,
and biological communities, known as stream environment
zones (“SEZ”s), remove sediments and nutrients. See Fink,
18 Ecology L.Q. at 494.

    Human activity in the late twentieth century, however,
began increasing nutrients and sediments in the lake, bringing
about a decline in clarity. Deposits tied to human activity
were to blame. See Holly Doremus, Reinvigorating the
Union of Wonder and Power, 24 Va. Envtl. L.J. 281, 285
(2005). According to scientists, the loss of clarity was tied to
nitrogen and phosphorous related to soil erosion, sewage
discharge, and runoff from impervious developments. Id.
More recently, scientists added to the list of threats
atmospheric deposits caused by rain washing nitrogen from
automobile exhaust down into the lake. Id. at 285–86; see
also Tahoe-Sierra Pres. Council, Inc. v. Tahoe Reg’l
Planning Agency, 322 F.3d 1064, 1070 (9th Cir. 2003)
(explaining the process of “eutrophication,” by which
nutrients encourage the growth of algae, which makes the
water greener and less clear and depletes oxygen in the water,
to the detriment of fish and other animals). As this court has
explained, artificial disturbance of the land, especially in
steeper areas and areas near streams and other wetlands,
greatly increases soil erosion and the flow of nutrients into
the lake. Tahoe-Sierra, 322 F.3d at 1070. There have been
other problems as well. As one district court put it, “[t]he
Lake Tahoe Basin has also suffered from degradation of other
measures of water and air quality. Many of the aesthetic and
recreational values of the region have been impaired,
including scenery, noise, and the ability to use the lake for
8                   SIERRA CLUB V. TRPA

recreational purposes.” League, 739 F. Supp. 2d at 1265.
These declines have been caused by onshore development,
piers and other structures in the lake, and emissions from
motorized watercraft. Id.

    The visible decline in water clarity led to efforts to reduce
discharges into the lake, beginning with prohibition of
sewage into any waters of the Tahoe basin. See Fink,
18 Ecology L.Q. at 504. In 1968, California and Nevada
entered into the first Regional Planning Compact, which
Congress approved in 1969. Suitum, 520 U.S. at 729. The
Compact created TRPA to serve as a bi-state land use and
environmental resource planning agency for the Lake Tahoe
Region. See id.; Compact art. I(b). TRPA’s governing board
includes a California delegation and a Nevada delegation,
with delegation members appointed by various state, county,
and city entities. Compact art. III(a)–(g). TRPA appoints an
advisory planning commission and employs an executive
officer and other staff and legal counsel. Compact arts. III(h),
IV(a).

    The original Compact also adopted a system, known as
the “Bailey system,” for classifying the environmental
sensitivity of the lands, with limits for the amount of
development on each type. See Tahoe-Sierra, 322 F.3d at
1070. That system remains as part of TRPA’s regulatory
scheme, but was not enforced with sufficient strictness to
protect the lake and its environment. As this court explained,
TRPA’s regulatory scheme, incorporating the Bailey system,
“was diluted in its implementation by numerous exceptions
permitting development on sensitive lands.” Id. at 1070–71.
In other words, some people thought the 1969 Compact was
not sufficiently anti-growth. See People, 766 F.2d at 1310.
                   SIERRA CLUB V. TRPA                        9

    In 1980, Congress therefore approved Compact
amendments, requiring TRPA to adopt a Regional Plan, and
barring any development exceeding environmental threshold
carrying capacities. Suitum, 520 U.S. at 729. The Compact,
as amended, requires that the Regional Plan include a land
use transportation plan, a conservation plan, a recreation plan,
and a public services and facilities plan. Compact art. V(c).
Pursuant to the 1980 Compact, TRPA has adopted multiple
threshold standards for, inter alia, water and air quality,
fisheries, and vegetation.

    TRPA adopted its first Regional Plan in 1984, but that
was challenged in court by the State of California, leading to
a reissuance of the Plan, adding a land classification system
that rated individual land parcels on their suitability for
development. The Individual Parcel Evaluation System, or
“IPES,” rated the land on a scale of 0 to 1150, and only those
above an “IPES Pass-Fail Line” were eligible to apply for
permission to develop parcels.

    Between 1987 and 2010, the 1987 Regional Plan was both
amended and litigated. See Tahoe-Sierra, 322 F.3d at
1073–74. In 1997, TRPA adopted the “Environmental
Improvement Program” as part of the Regional Plan to
improve water quality, yet, according to the 2012 RPU, the
primary pollutants affecting water clarity and quality
remained sediment, nitrogen, and phosphorous.

    The draft EIS for the RPU now before us concluded that
the 1987 Plan was largely successful in slowing growth and
making new development more environmentally compatible
by “tightly controlling” what could be built on vacant land.
It concluded that “the Tahoe region is now virtually at full
10                SIERRA CLUB V. TRPA

build-out, with less than 10% of the region’s development
rights remaining.”

    Unfortunately, as the draft EIS explained, buildings and
other uses put into place before the 1987 plan continue to
cause environmental problems. Hence, the 2012 RPU was
intended to address these issues. As described in the draft
EIS, the 2012 RPU was intended to “repair damage of the
past, while also promoting redevelopment of Tahoe’s
localized town centers to accelerate obtainment of threshold
standards with more environmentally appropriate and
attractive structures.”

   The RPU was developed by the Regional Plan Update
Committee of the TRPA governing board over a period of
nearly ten years. Indeed, the process took so long that
Nevada passed a bill calling for the state’s withdrawal from
TRPA if the plan were not updated in a timely manner. Nev.
Senate Bill 271 (2011).

    The RPU, adopted by TRPA’s board on December 12,
2012, and effective February 9, 2013, was meant to be a
general governing document for development and
environmental protection in the region, leaving more local
governance to Area Plans. Such Area Plans must conform to
the RPU.

    The RPU provided for the concentration of new and
existing development into “community centers.”           It
encouraged concentrated development by allowing TRPA
itself, or local governments, through the “Area Plans,” to
raise density, height, and coverage limits in community
centers. “Coverage” refers to the coverage of land with
impervious material such as asphalt and concrete. The RPU
                   SIERRA CLUB V. TRPA                       11

emphasized the Total Maximum Daily Load (“TMDL”)
model, which aims to reduce the total flow of certain
pollutants into the lake.

 REGULATORY HISTORY OF THE RPU AND ITS
                 EIS

     The events that occurred during the regulatory process
following the release of the draft EIS and draft RPU, and
leading to the issuance of the final EIS and final RPU, are
critical to the proper understanding of the issues in this case.

    The draft EIS and draft RPU were released in April 2012,
with a public comment period open for 63 days, from April
25 to June 28, 2012. The draft RPU and the draft EIS were
released for public comment on April 25, 2012, followed by
a series of meetings conducted by both California and Nevada
to make recommendations for amendments. TRPA’s
governing board voted to incorporate the revisions
recommended by the RPU Committee in August 2012, and
the final EIS was issued October 24, 2012.

    The RPU was undertaken concurrently with two related
planning efforts, a Regional Transportation Plan and a
Sustainable Communities Strategy. A separate EIS was
produced for these two projects. In addition, in 2011,
California, Nevada, and the Environmental Protection
Agency (“EPA”) approved the TMDL model, a water quality
restoration plan that aims to reduce the total flow of certain
pollutants into the lake. None of these efforts are affected
directly by this litigation, but they are central to TRPA’s
analysis in the RPU and EIS.
12                SIERRA CLUB V. TRPA

    During the public comment period on the draft RPU and
EIS, TRPA received comments that fill a large volume of the
final EIS. The California Attorney General submitted
extended comments.          She expressed concerns about
delegation of project approval via Area Plans, weakening of
coverage requirements, and allowance of potentially
significant amounts of new development. With regard to land
coverage, the Attorney General criticized the draft EIS’s
assumption that coverage could be calculated on a Basin-wide
basis without regard to location and concentration of
coverage. California was worried about concentrated
localized pollution in the lake. The Attorney General also
questioned TRPA’s allowance of coverage transfers and
mitigation across the boundaries of hydrologically related
areas, i.e., across different watersheds. With respect to the
effects of concentrated development, she stated that
watershed-level or even parcel-level analysis, rather than
region-wide analysis, was more consistent with the Bailey
system and with available science. The Attorney General
also questioned the draft EIS’s reliance on BMPs. She stated
that because the track record for maintaining BMPs at Lake
Tahoe was poor, the EIS “should disclose the history of
neglected BMP maintenance and disclose the impacts of its
alternatives assuming that past patterns of neglect continue
into the future.”

    Plaintiffs also submitted extensive comments addressing
many of the same issues. They expressed concerns that the
draft EIS, while analyzing impacts of coverage transfer on
Lake Tahoe itself, did not consider “soils, vegetation,
streams, fisheries and invertebrates within streams, and
sensitive habitat.” They pointed out that non-degraded soils
perform many functions, including “infiltration, erosion
prevention, vegetation growth, and nutrient cycling.”
                  SIERRA CLUB V. TRPA                     13

Plaintiffs complained that the draft EIS, in considering
coverage in developed areas, failed to analyze the effects on
streams and the nearshore of concentrating coverage.
According to Plaintiffs, the draft EIS “fails to acknowledge
studies that show that urban coverage is the most detrimental
coverage and fails to analyze the impact of increased and
concentrated urban coverage in the Basin.”

   Several commenters, including the California Tahoe
Conservancy and representatives of the EPA, expressed
concern about “the consistency between and coordinated
implementation of” the TMDL, the proposed RPU, and water
quality management.

    The final EIS included TRPA’s responses to all of the
comments received during the public comment period. While
generally concluding that the draft EIS was adequate, TRPA
made several significant changes to the draft RPU in response
to comments.

    TRPA’s “Master Response 3” addressed the California
Attorney General’s and Plaintiffs’ comments criticizing the
coverage standards established on a Region-wide basis and
permitting transfers of coverage allowances between
hydrologically related areas. TRPA’s response described the
relevant comments as expressing

       concern about the programmatic approach to
       coverage assessment presented in the Draft
       EIS, including the application of coverage
       standards on a Region-wide versus a parcel-
       by-parcel basis; potential undercounting of
       coverage by excluding consideration of some
       ‘soft’ coverage in the Basin; and the
14                  SIERRA CLUB V. TRPA

        differences in impact between hard and soft
        coverage.

TRPA explained that in response to these comments, it had
decided, among other things, to continue to prohibit coverage
transfers between hydrologically related areas, rather than to
start allowing such transfers in the RPU. TRPA pointed out,
however, that Region-wide, rather than parcel-by-parcel or
sub-watershed scale analysis was appropriate because the
RPU was regional in scope, and the Bailey method did not
require parcel-by-parcel analysis.

    In “Master Response 4,” addressing comments on
coordination between the RPU and the TMDL, TRPA
explained that it had made changes. The final RPU “includes
important new features that address the relationship between
the Regional Plan and the TMDL, specifically in the use of
the TMDL water quality improvement plan and TMDL
reporting information in the re-certification of Area Plans . . .
and revisions that create alignment in reporting
requirements.”

   In other Master Responses, TRPA addressed the
comments expressing concern about the effects of more
concentrated development on water quality.

        [C]omments suggest that policies
        incentivizing additional concentration of
        development in community centers could
        have localized adverse impacts on water
        quality, including on nearshore and tributary
        conditions. Concerns are expressed that the
        Draft EIS analysis does not adequately
        account for the fact that community centers
                    SIERRA CLUB V. TRPA                       15

        are near the Lake, pollutant loading may be
        higher in community centers than in outlying
        areas, and BMPs may not be adequate to
        mitigate the impact.

    TRPA stated its conclusion that the concerns were not
warranted, describing the draft EIS as “adequate as
presented,” and stating that “policies that incentivize transfers
of development and additional concentration of coverage in
specific areas would not result in significant impacts to water
quality.” Nevertheless, TRPA made modifications to the
draft RPU, which it said were required in order to “narrow the
scope of changes to coverage policies.” In addition, TRPA
prepared a “Pollutant Load Reduction Model” (“PLRM”)
stormwater modeling simulation, used to estimate localized
water quality impacts of concentrating development within
community centers. It added the PLRM to the final EIS in
order to better gauge the effect of concentrated development
on the lake.

    TRPA made other significant changes to the draft RPU as
well. In response to comments on the impact of revised
height and density allowances for community centers, the
final RPU included more scenic protections. In response to
comments about the feasibility of a program of incentives for
the transfer of development rights from sensitive and outlying
areas into designated community centers, the final RPU
retained the transfer incentive ratios set forth in the draft
RPU, but made revisions such as limiting allowances for
alternative transfer ratios for Stream Restoration Plan Areas.
TRPA also revised RPU provisions regarding banked assets
such as development rights in order to strengthen regulation
of their use. In response to comments about development on
recreation-designated lands, TRPA revised the draft RPU to
16                 SIERRA CLUB V. TRPA

reduce the areas to be re-designated and to require additional
planning and regulatory approvals through Area Plan
conformance review prior to any development on land
designated “Resort Recreation.” In connection with concerns
about exhaust emissions caused by vehicles traveling
additional miles because of additional development, the draft
RPU was revised in several ways, including the establishment
of additional limitations for the future expansion of
community centers.

     The California Attorney General had made significant
critical comments about the draft EIS’s reliance on BMPs that
had failed to be effective in the past. The final EIS included
a description of numerous efforts that were to be made to
improve the situation. It concluded that “[b]ased on the
current maintenance requirements and practices, education
efforts, and enforcement requirements . . . , it is valid to
assume that implementation of BMPs would be effective.”

   In response to comments about the approval process for
Area Plans, TRPA made some changes to the draft RPU’s
provisions regarding approval of Area Plans. TRPA added an
appeals process for all delegated projects, and it reduced the
maximum size of projects that could be reviewed and
approved by other agencies through an Area Plan.

     In summary, in response to negative comments,
particularly from the State of California and Plaintiffs, TRPA
made material revisions to the draft RPU and the draft EIS.
It retained the prohibition against coverage transfers between
hydrologically related areas. It coordinated the RPU more
closely with the TMDL. It cut back the proposed increases in
maximum allowable coverage for redevelopment projects in
community centers. It added more scenic protections, and it
                   SIERRA CLUB V. TRPA                     17

cut back draft RPU provisions regarding development on
recreation-designated land. It strengthened the process for
revising Area Plans. TRPA, specifically in response to
concerns about the concentrated effects of increased runoff,
added the PLRM stormwater modeling simulation to the final
EIS.

    TRPA issued the final EIS on October 24, 2012. The
final RPU was adopted by TRPA’s governing board on
December 12, 2012, and took effect on February 9, 2013.
Plaintiffs filed this lawsuit in the federal district court on
February 11, 2013. The district court granted TRPA’s motion
for summary judgment in April 2014, and these appeals by
plaintiff environmentalist organizations followed.

    This court has received amicus briefs in support of
affirming the district court by (1) City of Lake Tahoe, El
Dorado County, Placer County, California, Douglas County,
Carson City and County, and Washoe County, Nevada; and
(2) Lake Tahoe Community College, South Shore Chamber
of Commerce, North Lake Tahoe Chamber of Commerce,
Sierra Nevada Association of Realtors, Lake Tahoe Visitors
Authority, Tahoe Douglas Visitors Authority, South Tahoe
Alliance of Resorts and Barton Health. Perhaps most
significantly, the California Natural Resources Agency and
Nevada Department of Conservation and Natural Resources
have filed a joint amicus brief in support of TRPA.

              STANDING AND RIPENESS

    TRPA contends that Plaintiffs lacked standing to bring
this challenge to the impacts from the concentration of
development, and that their claims are unripe, because no
increase in coverage had yet been approved pursuant to any
18                 SIERRA CLUB V. TRPA

Area Plan. We disagree. Plaintiffs satisfy the injury-in-fact
requirement for standing to challenge the EIS because they
have concrete interests in the Lake Tahoe Region. See W.
Watersheds Project v. Kraayenbrink, 632 F.3d 472, 485 (9th
Cir. 2010). Their challenge is ripe because any violation of
the Compact or applicable environmental laws resulting from
the RPU and EIS has already taken place; Plaintiffs did not
need to wait for Area Plans to be approved before bringing
this suit. See id. at 486.

                STANDARD OF REVIEW

    We review the district court’s ruling on summary
judgment de novo. Protect Our Cmtys. Found. v. Jewell,
825 F.3d 571, 578 (9th Cir. 2016). Since TRPA is not a
federal agency, the Compact, and not the Administrative
Procedure Act (“APA”), provides the applicable standard of
review of TRPA actions.

    Under the Compact, “judicial inquiry shall extend only to
the questions of whether [TRPA’s legislative] act or decision
has been arbitrary, capricious or lacking substantial
evidentiary support or whether the agency has failed to
proceed in a manner required by law.” Compact art. VI(j)(5).
This standard is similar to review under the APA, which
provides that a federal agency action must be upheld unless
it is “‘arbitrary, capricious, an abuse of discretion, or
otherwise not in accordance with law.’” San Luis & Delta-
Mendota Water Auth. v. Jewell, 747 F.3d 581, 601 (9th Cir.
2014) (quoting 5 U.S.C. § 706(2)(A)), cert. denied, 134 S. Ct.
948 & 950 (2015); League, 739 F. Supp. 2d at 1267.
                   SIERRA CLUB V. TRPA                     19

    ANALYSIS OF PLAINTIFFS’ CONTENTIONS

I. Localized Effects of Concentrated Development

    Plaintiffs contend that the EIS violated Compact article
VII(a)(2)(A) by failing to take a hard look at impacts on soil
conservation and water quality in the localized “community
center” areas where concentrated development is directed.
We conclude that the EIS’s analysis of the effects of
concentrating development was not arbitrary or capricious,
and sufficiently addressed significant environmental impacts
of the RPU.

    TRPA may not amend the Regional Plan unless it finds
that the Plan, “as amended, achieves and maintains the
[threshold standards].” TRPA Code § 4.5; Sierra Club,
916 F. Supp. 2d at 1105. Article VII of the Compact requires
that “when acting upon matters that have a significant effect
on the environment,” TRPA must “[p]repare and consider a
detailed environmental impact statement.” Compact art.
VII(a)(2). This EIS must include, among other things:
“(A) The significant environmental impacts of the proposed
project; [and] (B) Any significant adverse environmental
effects which cannot be avoided should the project be
implemented.” Compact art. VII(a)(2)(A)–(B). The EIS
required by the Compact is similar to the EIS required by the
National Environmental Policy Act (“NEPA”), 42 U.S.C.
§ 4332(2)(C), and to the reporting required by the California
Environmental Quality Act, Cal. Pub. Res. Code § 21100.
Decisions under NEPA are authoritative. League, 739 F.
Supp. 2d at 1266, 1274; see also Glenbrook Homeowners
Ass’n v. Tahoe Reg’l Planning Agency, 425 F.3d 611, 615
(9th Cir. 2005) (stating that NEPA does not directly apply to
TRPA). An EIS is a procedural requirement with two
20                SIERRA CLUB V. TRPA

purposes: (1) ensuring that agencies carefully consider
information about significant environmental impacts, and
(2) informing the public of relevant information. Idaho Wool
Growers Ass’n v. Vilsack, 816 F.3d 1095, 1102 (9th Cir.
2016); Lands Council v. McNair, 629 F.3d 1070, 1075 (9th
Cir. 2010).

   The draft EIS conducted a region-wide analysis of the
impacts of increased coverage (meaning coverage of land
with concrete, asphalt, etc.). The draft EIS stated:

       Incentivizing coverage transfers and
       redevelopment by allowing up to 70 percent
       coverage on high-capacity developed parcels
       in [community centers] would increase
       coverage in these target areas. However, the
       additional coverage allowed on [these lands]
       would be directly offset by coverage
       transferred from sensitive land or more than
       offset on an acre-for-acre basis by transfers
       from high-capability land, resulting in an
       overall reduction of coverage in the Region
       and, importantly, reduction of coverage from
       SEZs [Stream Environment Zones] and other
       sensitive lands.

The draft EIS concluded that the proposed RPU (“Alternative
3” of the five alternative actions analyzed by TRPA) would
comply with the total allowable coverage for the Region as
determined by the Bailey system and would have a “less-
than-significant impact on coverage in the Region.” The draft
EIS also concluded that Alternative 3 would have a “less than
significant” impact on water quality.
                   SIERRA CLUB V. TRPA                      21

    In response to comments on the importance of soil
conservation at the local scale, TRPA explained that more
localized analysis would be too speculative at that stage. The
final EIS stated: “The Draft EIS evaluates coverage from a
programmatic policy perspective, with a level of detail and
degree of specificity appropriate to analysis of a Regional
Plan; a parcel-by-parcel analysis would be neither feasible
nor necessary.” TRPA further explained that even sub-
watershed analysis was infeasible because the agency would
be “forced to speculate where specific future projects would
be proposed and where coverage would be removed.”

    As the district court concluded, the RPU’s general shift
from the Bailey system, addressing coverage, to the TMDL
model, aimed at water quality restoration, was within TRPA’s
discretion. See Native Ecosystems Council v. Weldon,
697 F.3d 1043, 1051 (9th Cir. 2012) (holding, in a NEPA
case, that a court must be at its most deferential in reviewing
an agency’s scientific determinations).

    Plaintiffs contend, however, that the EIS violated
Compact article VII(a)(2)(A)’s requirement of environmental
analysis by addressing only the general region-wide impacts
of coverage changes, and failing to address the effects of
concentrated development on local watersheds in community
centers, where coverage is already high, even though
Plaintiffs, as well as the California Attorney General,
presented extensive evidence of these effects. Plaintiffs argue
that they did not seek study of site-specific project impacts,
but instead sought an analysis of the cumulative impacts of
many projects over larger areas, such as watersheds or sub-
watersheds. They contend that the public and decision
makers had no opportunity to weigh tradeoffs between
22                 SIERRA CLUB V. TRPA

cumulative impacts of local soil loss and any environmental
benefits of concentrated development.

    We can reject TRPA’s analysis of the effects of
concentrating development in community centers only if it is
arbitrary or capricious. See Compact art. VI(j)(5). It was not.
The final EIS adequately addressed concerns raised about the
draft EIS. As to water quality, the PLRM stormwater
modeling simulation, which was included in the final EIS,
addressed localized effects on those parts of the lake near
community centers. As described in the final EIS, the PLRM
simulation developed for the TMDL, part of the water quality
restoration plan approved by California, Nevada, and the
EPA, took into account available information. It incorporated
data “on land use types, impervious coverage, and BMP
implementation to generate estimates of fine sediment,
nitrogen, and phosphorus loading and stormwater runoff” in
order to “estimate the relative changes in pollutant loading
that could occur within community centers.” With regard to
water quality, the final EIS addressed effects of concentrated
development on a localized scale similar to the one advocated
by Plaintiffs. The final EIS adequately explained the basis
for its conclusion that concentrating development in
community centers would not result in more concentrated
runoff. The final RPU also maintained the prohibition of
transfers of coverage across watersheds. Under the TRPA
Code and the final RPU, all transferred coverage must come
from the same hydrologically related area. TRPA Code
§ 30.4.3.E.

    The final EIS also adequately addressed effects on soil
conservation. In studying the proposed RPU, a region-wide
plan, TRPA was not required to perform site-specific analysis
of impacts on soil conservation. As TRPA stated in response
                   SIERRA CLUB V. TRPA                       23

to comments, evaluation of coverage at a more localized scale
would occur, as part of the Area Plan process, prior to
development taking place. See Friends of the Wild Swan v.
Weber, 767 F.3d 936, 943 (9th Cir. 2014) (stating that agency
must balance need for comprehensive analysis against
considerations of practicality); Friends of Yosemite Valley v.
Norton, 348 F.3d 789, 800–01 (9th Cir. 2003) (holding that
deferral of site-specific analysis was proper under NEPA for
program-wide EIS), clarified by 366 F.3d 731 (9th Cir. 2004).
In addition, as TRPA argues, the PLRM simulation includes
soil conservation components.

     Contrary to Plaintiffs’ contention, the draft EIS addressed
cumulative effects on biological resources. With regard to
biological resources, the draft EIS also stated that Alternative
3, the RPU, “would result in increased permeability, reduced
urban runoff, and commensurate improvements in water
quality, soil conditions, and habitat for vegetation and
wildlife.” TRPA acted within its discretion in its choice of
scientific methodology, see Alaska Survival v. Surface
Transp. Bd., 705 F.3d 1073, 1088 (9th Cir. 2013), and its
organization and presentation of information in the EIS, see
Mont. Wilderness Ass’n v. Connell, 725 F.3d 988, 1002 (9th
Cir. 2013). TRPA was not required to conduct additional
scientific studies to determine an environmental threshold for
conservation of soil at a local or watershed level before
analyzing the impacts of region-wide coverage changes. See
N. Plains Res. Council v. Surface Transp. Bd., 668 F.3d 1067,
1085 (9th Cir. 2011) (stating that an agency is not required to
address every possible scientific uncertainty). The EIS’s
analysis of the effects of concentrating development was not
arbitrary or capricious, and did not violate Compact article
VII(a)(2)(A) by failing to address significant environmental
24                SIERRA CLUB V. TRPA

impacts of the RPU. See Compact art. VI(j)(5); Protect Our
Cmtys. Found., 825 F.3d at 578.

II. Best Management Practices

    Plaintiffs contend that TRPA improperly assumed,
without adequate analysis and hence in violation of Compact
article VII(a)(2)(A), that BMPs would reduce water quality
impacts of concentrated development under the RPU even
though TRPA has a poor track record of enforcing BMPs.
We conclude that the EIS’s assumptions regarding BMPs
were not arbitrary or capricious, and were supported by
substantial evidence. See Compact art. VI(j)(5).

     The TRPA Code provides that BMPs “shall be applied to
all public and privately owned lands.” TRPA Code § 60.4.2.
BMPs are described in the 2012 Handbook of Best
Management Practices, found in volume II of the Lake Tahoe
Basin Water Quality Management Plan. TRPA Code
§ 60.4.2. The RPU requires the installation and maintenance
of BMPs in accordance with the Handbook. The Handbook
states that BMPs are practices “that reduce or prevent the
pollutants of concern identified in the Lake Tahoe Total
Maximum Daily Load (TMDL) and other pollutants from
entering surface and ground waters.” The TRPA Code
provides for temporary BMPs for construction sites,
permanent BMPs for construction projects (as a condition of
project approval), and retrofit BMPs. TRPA Code §§ 60.4.3,
60.4.4.

    The TRPA Code and Handbook have several provisions
relating to maintenance and enforcement. The Code requires
that “BMPs shall be maintained to ensure their continued
effectiveness.” TRPA Code § 60.4.9. The Code provides
                   SIERRA CLUB V. TRPA                      25

that TRPA shall enforce BMP project compliance programs,
including the implementation and maintenance of temporary
BMPs on construction sites and the application of permanent
BMPs on projects. TRPA Code § 60.4.3. The Handbook
provides that BMPs “are designed to reduce the impacts of
stormwater pollutants and increased runoff on Lake Tahoe’s
famed clarity. Without regular maintenance, BMPs lose their
effectiveness, resulting in increased runoff and discharge of
pollutants to Lake Tahoe.” The Handbook acknowledges,
however, that maintenance of BMPs is “frequently
neglected.” Accordingly, the Handbook states that building
permits will require a BMP inspection and maintenance plan
as a condition of approval, and land owners and managers
will be required to keep inspection and maintenance logs.

    In its analysis of the effects of the RPU on water quality,
the draft EIS concluded that the effects of increased coverage
in community centers would be “less than significant”
because the additional coverage “would be required to meet
existing BMP standards to control potential increases in
stormwater runoff and pollutant loading . . . , including
maintenance requirements.” The draft EIS summarized
existing policies regarding BMP requirements and stated that
34% of land parcels in the Tahoe Region had obtained a BMP
Certificate by installing BMPs that met TRPA requirements.

    The reliance on BMPs in the draft EIS drew critical
comments. The California Attorney General commented that
the EIS “should disclose [the Region’s] history of neglected
BMP maintenance and disclose the impacts of its alternatives
assuming that past patterns of neglect continue into the
future.” Plaintiffs commented that for “longer term impacts
related to increased coverage – more runoff and the increased
pollutant loads from new construction – the alternatives that
26                SIERRA CLUB V. TRPA

allow more coverage need to have increased regulatory
authority (and stable funding) for inspections and
enforcement of coverage and BMP maintenance and
operation requirements for . . . new projects.”

    The final EIS responded that steps had been taken to
improve the situation and went on to explain what they were.
The final EIS stated: “Based on the current maintenance
requirements and practices, education efforts, and
enforcement requirements summarized below, it is valid to
assume that implementation of BMPs would be effective.”
The final EIS then listed TRPA Code § 60.4.9, BMP
Handbook Chapter 6, a Home Landscaping Guide for Lake
Tahoe and Vicinity, and a contractor’s manual that is
included in the curriculum of an annual BMP contractors
workshop conducted by TRPA. The final EIS also stated that
TRPA had received grant funding for BMP inspection, TRPA
inspectors enforce temporary BMP maintenance during
construction projects, TRPA had received grant funding for
a residential BMP maintenance video, TRPA had received
grant funding for the sending of BMP maintenance
reminders, and there were pending grant proposals related to
the enhancement of maintenance tracking. The final EIS
further explained that the RPU encouraged the use of area-
wide water quality treatment facilities, which could “lead to
more efficient maintenance practices relative to conducting
maintenance activities on many smaller and widely
distributed parcels and sites.”

    TRPA thus contends on appeal that the EIS properly
relied on BMPs and their effective implementation in support
of its conclusion that concentrated development would have
a less than significant impact on water quality. As TRPA
points out, the 2012 BMP Handbook acknowledges past
                    SIERRA CLUB V. TRPA                        27

failures in maintenance and incorporates that experience into
updated BMP guidelines. For example, according to the
Handbook, project permits require a BMP inspection and
maintenance plan, and land owners and managers are
required to keep inspection and maintenance logs. TRPA
also cites the public outreach programs listed in the final EIS
as part of the agency’s efforts to improve BMP maintenance.
See San Diego Navy Broadway Complex Coal. v. U.S. Dep’t
of Def., 817 F.3d 653, 660 (9th Cir. 2016) (holding that courts
may consider responses to comments for confirmation that an
agency has taken a “hard look” at an issue). We must
conclude that TRPA did not act arbitrarily and capriciously
in relying on its plan to better implement and maintain BMPs.
See Envtl. Prot. Info. Ctr. v. U.S. Forest Serv., 451 F.3d
1005, 1015–16 (9th Cir. 2006) (upholding an environmental
assessment for a timber sale under NEPA); Forest Guardians
v. U.S. Forest Serv., 329 F.3d 1089, 1099–1100 (9th Cir.
2003) (upholding a planned monitoring program for grazing
under the National Forest Management Act because it was
rational for the Forest Service to conclude that despite past
failures, monitoring should continue).

    Plaintiffs cite statistics regarding the relative lack of past
success of TRPA’s BMP retrofit program. As TRPA argues,
however, the RPU provides incentives for redevelopment and
thus is designed to move properties from TRPA’s retrofit
program into its mandatory permitting program for new
development, which requires BMP maintenance plans and
logs. TRPA reasonably relied on data in the record in
concluding that despite the agency’s imperfect past
enforcement of BMP maintenance, the RPU would have a
less-than-significant effect on water quality. See Lands
Council, 629 F.3d at 1076–77 (upholding a forest plan under
the National Forest Management Act). Plaintiffs cite Friends
28                  SIERRA CLUB V. TRPA

of Back Bay v. U.S. Army Corps of Eng’rs, 681 F.3d 581, 589
(4th Cir. 2012), where the court invalidated an environmental
assessment under NEPA because a boat speed limit that an
agency had not enforced was insufficient assurance that a
project’s boating impacts on wildlife would be mitigated. In
this case, TRPA provided significant assurances of future
enforcement. TRPA’s assumptions regarding BMPs were
supported by substantial evidence and are entitled to
deference. See Ctr. for Biological Diversity v. Bureau of
Land Mgmt., No. 14-15836, 2016 WL 4269899 at *9 (9th Cir.
Aug. 15, 2016).

III.    Costs

     The district court awarded costs pursuant to TRPA Rule
10.6.2, which provides that any agency costs in the
preparation of the administrative record for a legal action be
borne by the plaintiffs. Plaintiffs contend that the rule
unfairly makes them responsible for such costs even if they
prevail. Plaintiffs, however, did not prevail before the district
court, nor have they prevailed on appeal. Accordingly, we do
not need to address whether TRPA Rule 10.6.2 is a
statutorily-authorized exception to the general rule, set forth
in Federal Rule of Civil Procedure 54(d)(1), that costs should
be allowed to the prevailing party. Whether Rule 10.6.2 was
authorized by Compact art. VIII is a question for another day.
Because we affirm the district court’s decision in favor of
TRPA, the district court did not err in imposing costs, nor did
it abuse its discretion in denying Plaintiffs reimbursement for
certain costs. See Kalitta Air L.L.C. v. Cent. Tex. Airborne
Sys. Inc., 741 F.3d 955, 957 (9th Cir. 2013) (per curiam).
               SIERRA CLUB V. TRPA                      29

Plaintiffs’ request for judicial notice is denied as moot.

AFFIRMED.
