          United States Court of Appeals
                     For the First Circuit

No. 16-2280

                 CITY OF TAUNTON, MASSACHUSETTS,

                           Petitioner,

                               v.

         UNITED STATES ENVIRONMENTAL PROTECTION AGENCY,

                           Respondent.


             PETITION FOR REVIEW OF AGENCY ACTION OF
        THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


                              Before
                 Torruella, Lipez, and Thompson,
                         Circuit Judges.


     John C. Hall, with whom Philip D. Rosenman and Hall &
Associates were on brief, for petitioner.
     Sarah A. Buckley, Trial Attorney, United States Department of
Justice, Environment and Natural Resources Division, Environmental
Defense Section, with whom Jeffrey H. Wood, Acting Assistant
Attorney General, Environment and Natural Resources Division,
David J. Kaplan, Trial Attorney, and Samir Bukhari, Of Counsel,
United States Environmental Protection Agency, Region 1, were on
brief, for respondent.
     Michael Rubin, Assistant Attorney General, Rhode Island
Attorney General's Office, with whom Peter F. Kilmartin, Attorney
General, State of Rhode Island, on brief as amicus curiae.



                          July 9, 2018
             TORRUELLA,     Circuit    Judge.          The    City   of        Taunton,

Massachusetts       (the   "City"),    objects    to    the    decision         of   the

Environmental Protection Agency (EPA) to impose a limit -- through

a National Pollutant Discharge Elimination System (NPDES) permit

-- on the amount of nitrogen that the Taunton Wastewater Treatment

Plant (the "Facility") may discharge.             After considering all of

the City's challenges, both procedural and substantive in nature,

we uphold the EPA's permitting decision.

                                       I.

                                       A.

             It is useful to begin with an overview of the legal

landscape that is relevant to this appeal.                   The Clean Water Act

(CWA) prohibits the "discharge of any pollutant" unless that

discharge complies with NPDES permit requirements.                        33 U.S.C.

§§ 1311(a), 1342.          The EPA is responsible for issuing NPDES

permits unless a state agency is authorized to do so.                                Id.

§ 1342(a)-(c).       No Massachusetts agency is so authorized.                   Under

the   CWA,   NPDES    permits   must    include    any       water-quality-based

limitations that are necessary to ensure compliance with the water

quality standards of the state where the pollutant discharge in

question is to occur, as well as those of any affected downstream

states.       See    Id.   §§   1311(b)(1)(C),         1341(a)(2);        40    C.F.R.

§§ 122.4(d), 122.44(d)(4).        Giving effect to this requirement, EPA


                                       -2-
regulations     provide        that     NPDES     permits    "must    control    all

pollutants" that the EPA "determines are or may be discharged at

a level which will cause, have the reasonable potential to cause,

or contribute to an excursion above any State water quality

standard."      40 C.F.R. § 122.44(d)(1)(i); see also Arkansas v.

Oklahoma, 503 U.S. 91, 110 (1992) (explaining how this framework

incorporates state water quality standards into "the federal law

of water pollution control").

           NPDES permits issue for a period of time not to exceed

five   years.        33   U.S.C.      §§   1342(a)(3),      (b)(1)(B);   40   C.F.R.

§ 122.46(a).     Upon receiving a permit renewal application, the

permitting authority -- the EPA, in this case -- prepares a draft

permit setting out the proposed "effluent limitations, standards,

prohibitions     .    .    .   and     [other]     conditions."   1      40   C.F.R.

§ 124.6(d)(1), (d)(4)(v).             So too must the EPA issue a "fact sheet"

that "briefly set[s] forth the principal facts and the significant

factual, legal, methodological and policy questions considered in

preparing the draft permit."               Id. § 124.8(a).     The public comment


1  The noun "effluent" is defined as "the outflow of a sewer,
septic tank, etc." Webster's New World Dictionary & Thesaurus 195
(1996); see also 33 U.S.C. § 1362(11) ("The term 'effluent
limitation' means any restriction established by a State or the
Administrator on quantities, rates, and concentrations of
chemical, physical, biological, and other constituents which are
discharged from point sources into navigable waters, the waters of
the contiguous zone, or the ocean . . . .").


                                            -3-
period opens when the EPA publishes a public notice of the draft

permit.     After    reviewing     the    comments       submitted    during    that

period, the EPA issues a final permit decision along with a formal

"response to comments."          Id. §§ 124.15, 124.17(a).             "Any person

who filed comments on the draft permit or participated in a public

hearing on the draft permit may file a petition for review" of the

permit    with     the   Environmental         Appeals    Board      (EAB).       Id.

§ 124.19(a)(2).

                                         B.

            We also find it useful to provide a brief overview of

the facts and procedural events that are central to this appeal,

though we will also discuss those in greater detail in assessing

the City's various challenges.

            This appeal revolves around the NPDES permit that the

EPA issued for the Facility in 2015.             The City owns the Facility,

which also treats wastewater from the towns of Raynham and Dighton.

The Facility discharges into the estuarine portion of the Taunton

River,    which,   in    turn,   flows    into    Mount    Hope   Bay.        Located

partially in Rhode Island and partially in Massachusetts, Mount

Hope Bay is part of the larger Narragansett Bay.                  The Facility is

the second-largest point-source contributor of nitrogen to the

Taunton River watershed.2        Nitrogen pollution stimulates excessive


2   "The term 'point source' means any discernible, confined and

                                         -4-
plant growth in bodies of water, which can deprive waters of the

oxygen necessary to sustain other organisms -- a process called

"eutrophication."   See Upper Blackstone Water Pollution Abatement

Dist. v. EPA, 690 F.3d 9, 11-12 (1st Cir. 2012) (describing

eutrophication in greater detail).

          In 2005, the City applied to renew its soon-to-expire

2001-issued NPDES permit.      The 2001 permit did not limit the

Facility's discharge of nitrogen, but it did require nitrogen

monitoring.   The EPA issued a draft permit in 2007, but its review

of the ensuing public comments led it to conclude that it might be

necessary for the permit to impose nutrient limits.   After further

research, the EPA issued a superseding draft permit, along with

the mandatory accompanying fact sheet, in 2013.3        That draft

permit sought to limit the Facility's nitrogen discharges to an

average of 210 lbs. per day.   As the fact sheet explained, the EPA

found that limitation necessary after determining that the Taunton




discrete conveyance, including but not limited to any pipe, ditch,
channel, tunnel, conduit, well, discrete fissure, container,
rolling stock, concentrated animal feeding operation, or vessel or
other floating craft, from which pollutants are or may be
discharged." 33 U.S.C. § 1362(14). However, "[t]his term does
not include agricultural stormwater discharges and return flows
from irrigated agriculture." Id.
3  While the 2001-issued NPDES permit for the Facility expired in
2006, it was administratively continued pursuant to 40 C.F.R.
§ 122.6.


                                -5-
River and Mount Hope Bay "are suffering from the adverse water

quality impacts of nutrient overenrichment, including cultural

eutrophication,"     and   concluding        that    the   City’s    nitrogen

discharges had the "reasonable potential" to cause or contribute

to that overenrichment.     See 40 C.F.R. § 122.44(d)(1).

            At the City's request, the EPA extended the public

comment period to 90 days, during which time the City submitted a

substantial volume of comments objecting to the nitrogen limit

that the draft permit sought to impose on the Facility.             After the

extended public comment period closed, the City sought on multiple

occasions    to   submit   what   it    characterized      as   "supplemental

comments."    The EPA, however, rejected these as untimely, and

therefore declined to address them in its response to comments.

            After the final permit issued, the City appealed to the

EAB, challenging both the need for any nitrogen limit and the

specific limit that the permit imposed.             The City also filed two

motions before the EAB to supplement the record with, among other

things, the documents it had previously attempted to submit with

its "supplemental comments."       The EAB denied those motions. The

EAB also denied the City's administrative appeal on the merits,

along with the City's subsequent motion for reconsideration.             The

final permit went into effect on June 22, 2016.4


4   The permit did not require the City to give immediate effect to

                                       -6-
             The City then appealed to us, challenging this final

agency action, see 33 U.S.C. § 1369(b)(1)(F), on various procedural

and substantive grounds. After the parties filed their appellate

briefs, the EPA moved to strike certain portions of the City's

reply     brief    and    supplemental    appendix     because     they   involved

documents from outside of the agency record.5                 In response, the

City moved to supplement the record with the documents at issue.

The City also filed a motion "For Leave to Adduce New Material

Evidence and Compel Respondent's Review of the New Information."

We now resolve these motions and the merits of the City's appeal.

                                         II.

             The    Administrative       Procedure    Act   (APA)    governs      our

review of the EPA's actions and decisions amid the NDPES permitting

process.     See City of Pittsfield v. EPA, 614 F.3d 7, 10 (1st Cir.

2010).     Accordingly, we may only overturn what the EPA has done

if   we   find     that   it   was   "arbitrary,     capricious,    an    abuse   of

discretion, or otherwise not in accordance with law."                     5 U.S.C.

§ 706(2)(A).         More concretely, we are to leave agency action

undisturbed unless



its nitrogen limit, but rather set out a 10-year staged compliance
schedule for the City to follow.
5  We denied the State of Rhode Island's motion to intervene on
behalf of the EPA, but highlighted that it was free to "present
its position in an amicus curiae brief," which it then did.


                                         -7-
         the agency has relied on factors which Congress has
         not intended it to consider, entirely failed to
         consider an important aspect of the problem, offered
         an explanation for its decision that runs counter to
         the evidence before the agency, or is so implausible
         that it could not be ascribed to a difference in view
         or the product of agency expertise.

Motor Vehicle Mfrs. Ass'n of U.S., Inc. v. State Farm Mut. Auto.

Ins. Co., 463 U.S. 29, 43 (1983).         "This deference goes to the

entire agency action, which here includes both the EPA's permitting

decision and the EAB's review and affirmance of that decision."

Upper Blackstone, 690 F.3d at 20.

           Here, the "scientific and technical nature of the EPA's

decisionmaking" increases our level of deference.              Id. (citing

Balt. Gas & Elec. Co. v. Nat. Res. Def. Council, Inc., 462 U.S.

87, 103 (1983) (explaining that when an agency is acting "within

its area of special expertise, at the frontiers of science . . . .

as opposed to [making] simple findings of fact, a reviewing court

must generally be at its most deferential")).       We are particularly

mindful that "where a complex administrative statute, like those

the EPA is charged with administering, requires an agency to set

a numerical standard, courts will not overturn the agency's choice

of   a   precise   figure   where    it   falls   within   a     'zone   of

reasonableness.'" Upper Blackstone, 690 F.3d at 28.

           Similarly, because interpreting and implementing the CWA

falls squarely within the EPA's bailiwick, see Adams v. EPA, 38


                                    -8-
F.3d   43,   49   (1st   Cir.   1994),    we   defer   to    its   "reasonable

interpretation" of that statute, Upper Blackstone, 690 F.3d at 21.

See also Chevron, U.S.A., Inc. v. Nat. Res. Def. Council, Inc.,

467 U.S. 837, 843 (1984) ("[I]f the statute is silent or ambiguous

with respect to the specific issue, the question for the court is

whether the agency's answer is based on a permissible construction

of the statute.").        Finally, the EPA enjoys greater deference

still when interpreting its own regulations.                Upper Blackstone,

690 F.3d at 21.     Its interpretation of those regulations shall be

"controlling unless 'plainly erroneous or inconsistent with the

regulation.'"     Auer v. Robbins, 519 U.S. 452, 461 (1997) (quoting

Robertson v. Methow Valley Citizens Council, 490 U.S. 332, 359

(1989)).

                                     A.

1.

             After briefing before this court concluded, the EPA

moved to strike certain documents in the City's supplemental

appendix, in addition to parts of the City's reply brief that cited

those documents, as outside of the administrative record.               These

documents comprised: (1) a 2005 Rhode Island nutrient policy

document; (2) slides prepared by the Narragansett Bay Commission;

and (3) a draft report from the Narragansett Bay Estuary Program

(the "draft NBEP report").       In response, the City cross-moved to


                                    -9-
supplement the record.      The City argued that it was entitled to

refer to the documents at issue in rebutting arguments that the

State    of    Rhode   Island   had     raised   in   its   amicus   brief.

Specifically, the City pointed to Rhode Island's contentions that:

(1) "The fact that [the Rhode Island Department of Environmental

Management's] nitrogen limitations for numerous in-state sewage

treatment plants are numerically consistent with the nitrogen

limitation at issue further corroborates the reasonableness of the

EPA’s decision"; (2) the nitrogen limit that the EPA imposed in

the Permit is necessary to ensure compliance with Rhode Island's

water quality standards; and (3) that research by the Narragansett

Bay Estuary Program and the University of Rhode Island Coastal

Institute bolster the EPA's decision.

              At the foreground of our analysis here is the principle

that, when reviewing an agency's decision under the arbitrary and

capricious standard, "the focal point for judicial review should

be the administrative record already in existence, not some new

record made initially in the reviewing court."         Camp v. Pitts, 411

U.S. 138, 142 (1973); see also Fla. Power & Light Co. v. Lorion,

470 U.S. 729, 744 (1985) ("[I]f the reviewing court simply cannot

evaluate the challenged agency action on the basis of the record

before it, the proper course, except in rare circumstances, is to

remand    to     the   agency    for     additional    investigation    or


                                      -10-
explanation.");        Walter O. Boswell Mem'l Hosp. v. Heckler, 749

F.2d   788,    792   (D.C.    Cir.     1984)    ("To   review   more   than   the

information before the Secretary at the time she made her decision

risks our requiring administrators to be prescient or allowing

them to take advantage of post hoc rationalizations." (citing Am.

Petrol. Inst. v. Costle, 609 F.2d 20, 23 (D.C. Cir. 1979))).

              Yet, exceptions do exist.          We have recognized a pair of

situations in which we have the discretion to supplement the agency

record.    Town of Winthrop v. FAA, 535 F.3d 1, 14 (1st Cir. 2008).

First, we may consider supplemental evidence to facilitate our

comprehension     of    the   record    or     the   agency's   decision.     Id.

Examples   of    this    include     agency     decisions   involving   "highly

technical, environmental matters," Valley Citizens for a Safe

Env't v. Aldridge, 886 F.2d 458, 460 (1st Cir. 1989) (Breyer, J.),

or when we are faced with a "failure to explain administrative

action as to frustrate effective judicial review," Olsen v. United

States, 414 F.3d 144, 155-56 (1st Cir. 2005) (quoting Camp, 411

U.S. at 142-43).         Second, a "strong showing of bad faith or

improper behavior" may also provide occasion to "order[] the

supplementation of the administrative record."                  Town of Norfolk

v. U.S. Army Corps of Eng'rs, 968 F.2d 1438, 1458-59 (1st Cir.

1992) (citing Citizens to Preserve Overton Park, Inc. v. Volpe,

401 U.S. 402 (1971)).


                                        -11-
          We note that the City's proffered justification for

supplementing the record -- to allow it to respond to arguments

raised in an amicus brief -- does not fit neatly within either of

these exceptions.6    Without passing judgment on whether that is a

categorically inadequate reason to supplement the agency record,

we find that the City has failed to convince us here that we should

exercise our discretion in this manner.

          Keeping in mind that our broader adjudicatory task here

is to determine whether, on the basis of the record before it, the

EPA acted arbitrarily or capriciously, we take note of the City's

position that Rhode Island's "assertions were not the basis of

[the] EPA's permit limit calculations," and that Rhode Island's

scientific and factual averments "were not part of the underlying

agency[] decision."    It would follow, then, that Rhode Island's

assertions also cannot provide a basis for our affirmance of the


6   The City also insists that this is a situation when
supplementing the record is appropriate because "the good faith of
the agency is at issue." The City appears to argue that the EPA
shirked its "duty" to "bring forth" the information contained in
the draft NBEP report -- which the City says undercuts the EPA's
conclusions regarding the permit -- and that we can infer bad faith
from this. But, the draft NBEP report is dated April 2017, which
is ten months after the final permit went into effect, following
the City's unsuccessful administrative appeal. Setting aside the
question of whether the draft NBEP report (or its subsequently
published final iteration) actually supports the City's position
-- which the EPA sharply contests -- we fail to see how the EPA's
failure to engage with a document that didn't exist at the time of
its permit decision can amount to indicia of bad faith.


                                -12-
EPA's permit decision.    So, we do not find it appropriate or

necessary to allow the City to go beyond the agency record to rebut

those assertions.7

          Because the City has not convinced us that the record

should include the documents at issue in the EPA's motion to strike

and the City's cross-motion to supplement the record, we grant the

former and deny the latter.

2.

          Before oral argument, the City also brought a motion

"For Leave to Adduce New Material Evidence and Compel Respondent's

Review of the New Information."   The City anchored that motion in


7  To the extent that the City seeks to cite these documents not
to rebut Rhode Island's arguments but rather to attack the merits
of the EPA's permit decision (a motive at which its reply brief
hints), we emphasize that the proper moment for the City to adduce
evidence to that effect was the public comment period. See Cousins
v. Sec'y of U.S. Dep't of Transp., 880 F.2d 603, 610 (1st Cir.
1989) (reasoning that parties are not prejudiced by the principle
that our review is limited to the agency record because they are
free to contribute to that record amid proceedings before the
agency).   Further, to the extent that the City argues that the
draft NBEP report -- which, again, post-dates the permit decision
-- should come into the record as evidence that the EPA's permit
decision was arbitrary and capricious, we also disagree.        We
repeat that our review is of the agency's decision based on the
record before it.      Setting aside whatever merit the City's
arguments concerning the substance of that report may have, we
recall one of the reasons motivating our limited scope of review:
"[T]he hope or anticipation that better science will materialize
is always present, to some degree, in the context of science-based
agency decisionmaking. Congress was aware of this when it
nonetheless set a firm deadline for issuing new permits." Upper
Blackstone, 690 F.3d at 23.


                               -13-
section 509(c) of the CWA, see 33 U.S.C. § 1369(c), which, the

City claims, gives us the authority to compel the EPA "to review

material evidence that arises after the challenged EPA action."

          But we do not agree.     Section 509(c)'s own terms limit

its application to agency "determination[s] . . . required to be

made on the record after notice and opportunity for hearing."      Id.

(emphasis added).   That is crucial because the phrase "on the

record" serves to invoke formal agency adjudication under the APA.

See 5 U.S.C. § 554(a); United States v. Allegheny-Ludlum Steel

Corp., 406 U.S. 742, 757 (1972) (explaining, in the context of

agency rulemaking, that the APA's provisions governing formal

agency proceedings, see 5 U.S.C. §§ 556-57, apply when "the agency

statute, in addition to providing a hearing, prescribes explicitly

that it be 'on the record'" (quotation omitted)).        Thus, section

509(c) applies only to formal agency adjudications.       Congress has

specified only that the EPA is to issue NDPES permits "after

opportunity for public hearing," without specifying whether that

hearing must be "on the record."        33 U.S.C. §§ 1326(a), 1342(a).

But, we have afforded Chevron deference to EPA regulations setting

forth -- in light of Congress's silence on this issue -- that these

public hearings need not be "on the record," and that the NDPES

permit process is therefore an informal agency adjudication under




                                 -14-
the APA.    Dominion Energy Brayton Point, LLC v. Johnson, 443 F.3d

12, 14-15, 18-19 (1st Cir. 2006).

             This forecloses the City's argument.              Because the agency

record at issue here pertains to an informal adjudication, section

509(c) of the CWA is inapposite, and does not provide a basis for

us to order the EPA to reopen the administrative record to consider

the City's purportedly new material evidence.                     As a result, we

deny the City's motion for us do to so.

                                          B.

             We turn now to the various procedural challenges that

the City brings.

1.

             The City first tells us that the EPA "failed to provide

public access to fundamental evaluations, analyses, and data used

to derive the permit."        While the City's precise objections are

perhaps    not    the   easiest     to   discern,    we    read     its    brief    as

essentially       asserting   two    things:      (1)     that    the     factsheet,

containing       only   "generalized      supporting      information       for    the

stringent     nutrient    limitations,"         failed    to     provide    adequate

support for the draft permit's nitrogen limitation, and (2) that

"when challenged regarding the adequacy of that documentation,

[the EPA improperly] add[ed] thousands of pages of site-specific

studies, data analyses and specific regulatory findings [to the


                                         -15-
final administrative record], after the comment period closed."

The appropriate remedy, according to the City, is for us to order

the EPA to reopen the public comment period so that the City may

weigh in on the "new justifications and analyses supporting [the]

permit"   for   which   the   EPA   allegedly    deprived    the   City    of   a

"rebuttal opportunity."8

           We start with the City's claim that the fact sheet was

facially deficient.      Under 40 C.F.R. § 124.8(a), the fact sheet

that accompanies a draft NPDES permit need only "briefly set forth

the   principal    facts      and   the     significant     factual,      legal,

methodological and policy questions considered in preparing the

draft permit."    We find that, here, the fact sheet satisfied that

requirement.

           First, the fact sheet explained how the EPA had arrived

at its conclusion that the "Taunton River Estuary and Mount Hope

Bay have reached their assimilative capacity for nitrogen," and as



8  The City's briefing broadly describes its various procedural
challenges in terms of due process violations or violations of its
procedural rights. However, we do not understand the City to be
raising a Fifth Amendment Due Process Clause claim. Rather, the
City's contentions fall under the ambit of the APA. We thus apply
arbitrary and capricious review to the City's procedural claims.
See United States v. Estate of Boothby, 16 F.3d 19, 21 (1st Cir.
1994) ("In scrutinizing administrative action, a reviewing court
is free to correct errors of law, but, otherwise, the court is
limited to a search for arbitrary or capricious behavior.") (citing
5 U.S.C. § 706(2)(A)).


                                     -16-
a result, were already "failing to attain the water quality

standards" that Massachusetts and Rhode Island law impose.              The

fact sheet then explained the EPA's conclusion that, because the

Facility's nitrogen discharges had the "reasonable potential" to

cause violations of the applicable water-quality standards, it was

necessary to include an effluent limit in the draft permit.            Next,

the fact sheet detailed how the EPA first calculated the threshold

nitrogen concentration for the Taunton River Estuary -- that is,

the maximum amount of nitrogen that the Estuary may contain before

any water-quality violations result -- and then calculated an

"allowable total nitrogen load from the watershed" that would keep

the Estuary's nitrogen concentration at or below that threshold.

Finally, the fact sheet laid out how the EPA allocated that total

allowable nitrogen load among the Estuary's various point-sources

of nitrogen -- including the Facility -- to derive limits for each

of those nitrogen dischargers.          At each step, the EPA identified

the    datasets    and   studies   it    relied   upon   in   making   these

calculations, and provided a clear account of its reasoning and

underlying assumptions.

              In light of all of this, we do not agree with the City

that    the    fact   sheet   provided     only   "generalized   supporting

information for the stringent nutrient limitations."             Quite the

opposite, the fact sheet described in substantial detail the


                                    -17-
methodology   that   the       EPA    employed     in   deriving   the    nitrogen

limitation that it ultimately imposed in the draft permit.                      The

City therefore fails to convince us that the fact sheet ran afoul

of the regulations governing it.9              Having resolved that, we now

turn to the City's claim that the EPA improperly added documents

to the final administrative record.

            According     to    the   City,    a   "quick   comparison     of   the

original 20-page generalized fact sheet discussion versus the 80

pages of site-specific analysis contained in the [response to

comments]   and   final    administrative          record   confirms     extensive

revisions occurred."10         The City also protests that the fact sheet


9  In its reply brief, the City contends that the fact sheet was
inadequate for many of the same reasons for which it claims that
the final permit's nitrogen limit was arbitrary and capricious
(e.g., it failed to consider "the post-2006 system wide pollutant
reductions affecting algal growth and [dissolved oxygen]"). In
addition to having been waived, see Waste Mgmt. Holdings, Inc. v.
Mowbray, 208 F.3d 288, 299 (1st Cir. 2000) ("We have held, with a
regularity bordering on the monotonous, that issues advanced for
the first time in an appellant's reply brief are deemed waived."),
these arguments, as we explain in addressing the City's substantive
challenges, also lack merit.
10  To the extent that the City argues that the final permit
departed impermissibly in substance from the draft permit, we
recall that an agency "can make even substantial changes from the
proposed version [of a rule], as long as the final changes are 'in
character with the original scheme' and 'a logical outgrowth' of
the notice and comment." Nat. Res. Def. Council, Inc. v. EPA, 824
F.2d 1258, 1283 (1st Cir. 1987) (quoting S. Terminal Corp. v. EPA,
504 F.2d 646, 658 (1st Cir. 1974)); see also In Re Town of Concord
Dep't of Pub. Works, 16 E.A.D. 514, 532-33 (EAB 2014) (upholding
the decision not to reopen public comment after rejecting the Town
of Concord's argument that the pH limit imposed in a final NPDES

                                        -18-
and its supporting documentation suffered from "glaring record

omissions," and that it was only at the Final Permit stage that

the EPA "disclosed the new information, evaluations, data, and

conclusions that purportedly justified its action."

            The EPA's rejoinder is that, as the EAB explained, "it

is both permissible and expected for [the EPA] to place new

material    in    the     Administrative     Record    when   responding     to

significant comments."        The EPA also correctly points out that its

regulations provide that if "new points are raised or new material

supplied during the public comment period, EPA may document its

response   to     those    matters   by    adding    new   materials   to   the

administrative record."           40 C.F.R. § 124.17(b); see also id. §

124.18(b)(4) (the administrative record for a final permit must

include "the response to comments required by § 124.17 and any new

material placed in the record under that section").              And it does

not follow that, because the EPA added new materials to the

administrative record in response to comments it received, it also

needed to reopen the comment period.                The relevant regulations

provide    that   "[i]f     any    data[,]   information[,]    or   arguments

submitted during the public comment period . . . appear to raise




permit was not a "logical outgrowth" of the draft permit). And
the City offers nothing in support of any contention that the final
permit was not a "logical outgrowth" of the draft permit.


                                      -19-
substantial new questions concerning a permit, the [EPA] may . . .

[r]eopen or extend the comment period."                 40 C.F.R. § 124.14(b)

(emphasis added).       In the end, the City fails to convince us that

the EPA wrongly declined to exercise its discretion to reopen the

comment period after adding new documents to the administrative

record.

            Contrary      to    what    the      City   asserts,   the   60-page

difference between the fact sheet and the response to comments

does    little   to    suggest     that    the    EPA   acted   arbitrarily     or

capriciously.      Because it needed only to "briefly set forth" the

draft   permit's      factual    and   theoretical      underpinnings,   see   40

C.F.R. § 124.8(a), the fact sheet's comparative brevity cannot

alone be indicative of any illegitimate additions to the response

to comments.     We, therefore, do not agree with the City that the

EPA acted arbitrarily or capriciously in adding documents to the

record after the public comment period.                 Nor does the City give

us any reason to conclude that the EPA needed to reopen the public

comment period after adding those documents.

2.

            The City next challenges the EPA's decision not to

address   the    City's    untimely       "supplemental     comments"    in    the

response to comments.          40 C.F.R. § 124.17(a)(2) requires only that

the EPA "[b]riefly describe and respond to all significant comments


                                       -20-
on the draft permit . . . raised during the public comment period,

or during any hearing." (emphases added); see also id. § 124.13

("All persons . . . who believe any condition of a draft permit is

inappropriate . . . must raise all reasonably ascertainable issues

and submit all reasonably available arguments supporting their

position by the close of the public comment period.").    As we have

explained previously, we apply "strict rules of procedural default

in the administrative context" for a number of reasons:

        First, when the administrative agency is given an
        opportunity to address a party's objections, it can
        apply   its    expertise,    exercise   its  informed
        discretion, and create a more finely tuned record for
        judicial review . . . . A second reason for applying
        strict   rules    of   procedural   default  in   the
        administrative context is to promote judicial economy
        . . . . Finally, enforcing procedural default
        solidifies the agency's autonomy by allowing it the
        opportunity to monitor its own mistakes and by
        ensuring that regulated parties do not simply turn to
        the courts as a tribunal of first resort.

Adams, 38 F.3d at 50 (quoting Mass. Dep't Pub. Welfare v. Sec'y of

Agric., 984 F.2d 514, 523 (1st Cir. 1993)).     The City does not

proffer any good reason for us to deviate from these principles

here.   And while the EPA was free to reject the City's untimely

comments out of hand, it nonetheless undertook to review them.

Thus, the EPA concluded in the response to comments that those

untimely comments pertained in large part "to the subject matter

of the City's timely submitted comments, which have been duly

considered."   The EPA then added that "[g]iven the foregoing, and

                               -21-
the fact that the existing permit is long expired, the evidence of

ongoing water quality impairments, and the need . . . for timely

imposition of more stringent nutrient controls, EPA rejects the

'supplemental comments' as untimely."                  It therefore declined to

respond to those comments.               We do not find this to have been

arbitrary or capricious.

             We    similarly    uphold     the    EAB's       decision   to   strike

documents that the City attempted to submit for the first time at

the administrative appeal stage.                  The City protests that the

EAB's decision "effectively created a double-standard whereby [the

EPA] may include extensive new post-comment period analyses and

data   to    justify   its    action,    yet     the   City    is   precluded   from

commenting on any of this new information."                    But this assertion

alone -- especially given our rejection of the notion that the EPA

illicitly added information to the final record or that the final

permit departed impermissibly from the fact sheet and draft permit

--   fails    to   convince    us   that   the     EAB    acted     arbitrarily   or

capriciously in policing its waiver rule.                See 40 C.F.R. §§ 124.13,

124.19 (requiring that permit appellants raising new arguments

"explain why such issues were not required to be raised during the

public comment period").            We therefore conclude that the EAB

properly refused to consider these new documents.




                                        -22-
3.

          Finally, the City tells us that "following the issuance

of its deficient fact sheet, EPA repeatedly stymied Taunton's

access to the Agency's back-up documentation allegedly supporting

the contested [total nitrogen] limitation."    In brief, the City

makes much ado over the EPA's purported unwillingness to allow the

City to see documents supporting the draft permit's nitrogen limit.

The City's briefing does not make entirely clear what exactly it

wanted the EPA to do.    But in any event, we note that the City

does not argue that the EPA ran afoul of any applicable legal

requirement.   And as the EPA points out, it needed only to provide

physical access to the record during the public comment period,

see 40 C.F.R. § 124.10(d)(1)(vi), which it did.   As it turns out,

the EPA invited representatives of the City to visit its Region

One office in Boston to review the administrative record on

multiple occasions.   The City, meanwhile, expressly rejected that

invitation.    In sum, because the City fails to show that it was

procedurally entitled to anything more than what the EPA afforded

it, we do not find the EPA's actions in this respect to have been

arbitrary or capricious.    See Vt. Yankee Nuclear Power Corp. v.

Nat. Res. Def. Council, Inc., 435 U.S. 519, 524 (1978)   ("Agencies

are free to grant additional procedural rights in the exercise of




                               -23-
their discretion, but reviewing courts are generally not free to

impose them if the agencies have not chosen to grant them.").11

                                            C.

               We now take up the City's substantive challenges to the

Permit and its nitrogen limit.

1.

               The first arrow that the City pulls from its quiver is

that the EPA erred in determining that the Taunton Estuary was

nutrient impaired.

               As we explained above, NPDES permits "must control all

pollutants or pollutant parameters" that the EPA "determines are

or may be discharged at a level which will cause, have the

reasonable potential to cause, or contribute to an excursion above

any    State    water     quality       standard,    including    State   narrative

criteria for water quality."               40 C.F.R. § 122.44(d)(1)(i).         The

EPA has interpreted "reasonable potential" to mean "some degree of

certainty      greater     than     a    mere     possibility."     In    re   Upper

Blackstone Water Pollution Abatement Dist., 14 E.A.D. 577, 599

n.29    (EAB     2010).      "Narrative"          water   quality   criteria    are


11  The City also submits that the "EPA's recalcitrance was so
pronounced that it prompted a federal court to award attorneys'
fees against EPA under FOIA."       This is irrelevant, though.
Whatever obligations the EPA may have had in connection with any
particular FOIA request have no bearing on the EPA's compliance
with the framework governing the NPDES permit process.


                                           -24-
qualitative, rather than numerical, in nature.                 See 40 C.F.R.

§§ 131.3(b), 131.11 (b).

             Massachusetts classifies the Taunton Estuary and the

eastern portion of Mount Hope Bay as "Class SB" waters.               Per state

regulations, Class SB waters "are designated as a habitat for fish,

other aquatic life and wildlife . . . and for primary and secondary

contact recreation."          314 Mass. Code Regs. § 4.05(4)(b).             They

"shall have consistently good aesthetic value."                Id.     Class SB

waters must also meet the numeric water quality criterion of a

minimum of 5.0 mg/l of dissolved oxygen.           Id. § 4.05(4)(b)(1).       So

too   must   they   satisfy     the    following   narrative   water     quality

criterion:

        Unless naturally occurring, all surface waters shall
        be free from nutrients in concentrations that would
        cause or contribute to impairment of existing or
        designated uses . . . . Any existing point source
        discharge containing nutrients in concentrations that
        would cause or contribute to cultural eutrophication
        . . . shall be provided with the most appropriate
        treatment . . . to remove such nutrients to ensure
        protection of existing and designated uses.

Id. § 4.05(5)(c).

             When   issuing    NDPES    permits    for   states   that    employ

narrative criteria, the EPA must translate those criteria into a

"calculated     numeric   water       quality   criterion"     that    the    EPA

"demonstrates will attain and maintain applicable narrative water

quality criteria and will fully protect the designated use."                  40


                                       -25-
C.F.R.    §    122.44(d)(1)(vi)(A).               The    EPA    may    arrive     at    that

numerical criterion by using "a proposed State criterion, or an

explicit State policy or regulation interpreting [the State's]

narrative      water      quality      criterion,        supplemented       with       other

relevant      information     .    .   .   ."      Id.         Massachusetts      has    not

prescribed specific methodologies for deriving numeric nitrogen

limitations       that    correspond       to   its      narrative       criteria.       It

therefore fell to the EPA to do so here.

              The EPA looked to an interim report prepared for the

Massachusetts Department of Environmental Protection (MassDEP)

known as the "Critical Indicators Report."                            See Massachusetts

Estuaries       Project,      Site-Specific             Nitrogen       Thresholds        for

Southeastern Massachusetts Embayments: Critical Indicators, July

21,       2003,          https://www.mass.gov/files/documents/2016/08/mp/

nitroest.pdf (last visited June 14, 2018).                       As the EPA explained

in the response to comments, "[w]hile MassDEP has not adopted the

Critical Indicators Report as a specific policy, it has afforded

the document technical and scientific weight, [and] has explicitly

relied on the report" in other regulatory contexts.

              The purpose of that report is to provide a "translator"

between    Massachusetts's          narrative      water       quality    standard      and

corresponding       numeric       nitrogen      thresholds        that    would    ensure

compliance with those standards.                   Id. at 2.          To that end, the


                                           -26-
report     listed    various     criteria,      or   "indicators,"      to        guide

assessments of the present health of a given body of water,

including the amount of oxygen, nitrogen, and chlorophyll present

in that body.12      Id. at 11.          In this sense, those "indicators"

serve as factors to consider when assessing how healthy a body of

water is.     The interim report also provided what it describes as

"straw man" threshold levels -- to be "further refined with the

collection of additional data and modeling."                   Id. at 3.            For

example, per those thresholds, Class SB waters are not impaired

when, among other things, "oxygen levels are generally not less

than 5.0 mg/l," chlorophyll-a levels are between 3-5 µg/l, and

nitrogen    levels    are      between    0.39-0.50    mg/l.      Id.        at     22.

"Moderately impaired" SB waters have oxygen levels that "generally

do not fall below" 4.0 mg/l, chlorophyll levels that may reach 10

µg/l, and nitrogen concentrations above roughly 0.5 mg/l.13                         Id.




12  As the Critical Indicators Report explains, the amount of
chlorophyll in a given body of water provides a measure of the
concentration of aquatic plant life in that water, and therefore
indicates the extent to which eutrophication has occurred. Id.
at 14.
13  The case studies giving rise to these figures indicated,
according to the report, that regions with nitrogen concentrations
above 0.5 mg/l were "clearly impaired," while certain locations
began showing signs of impairment once nitrogen exceeded 0.4 mg/l.
Id. at 23.


                                         -27-
at 23.     Class SB waters are "significantly impaired," according

to the report, at around 0.6-0.7 mg/l of nitrogen.                Id.

             The EPA then looked to data from a three-year water

quality monitoring study that the School for Marine Sciences and

Technology at University of Massachusetts Dartmouth (SMAST) had

carried out.       The study involved taking monthly water samples from

22 sites across the Taunton Estuary and Mount Hope Bay from 2004

to 2006.     The study revealed that all of these sites were suffering

from excessive algae growth; each site had an average chlorophyll-

a concentration of over 10 µg/l during the study's three-year

period.    All 22 monitoring stations also had an average dissolved

oxygen concentration below 5.0 mg/l during that period.                   And in

the   case    of    16    monitoring    stations,     the     average    nitrogen

concentration exceeded .5 mg/l -- where the Critical Indicators

Report    drew     the   line   for   "clearly    impaired"    waters.     Those

monitoring stations located in the Taunton River tended to have

the   highest      nitrogen     concentrations.     The     monitoring   station

closest to the Facility's discharge point showed a particularly

high nitrogen concentration -- ranging from 0.66 to 0.99 mg/l

during the course of the study.

             The EPA also considered data from another monitoring

station in Mount Hope Bay, operated by the Narragansett Bay Water

Quality Network.          That data showed that the dissolved oxygen


                                       -28-
concentration       at    that    site    fell   below    4.8   mg/l    on   multiple

occasions in 2005 and 2006.              On two such occasions, the dissolved

oxygen    concentration          remained   below   2.9    mg/l   for     two   days,

resulting in "hypoxic conditions," or "levels of dissolved oxygen

below what is needed by aquatic organisms to breathe," Upper

Blackstone, 690 F.3d at 12.           The data also showed "multiple events"

of chlorophyll-a concentrations exceeding 20 µg/l.                     Moreover, the

data from the monitoring station indicated that the site continued

to   suffer    from        elevated       chlorophyll-a     concentrations        and

persistent dissolved oxygen concentrations below 5 mg/l in 2010.

             The EPA then applied the SMAST and Mount Hope Bay data

to the Critical Indicators Report.               This led it to conclude that

"cultural eutrophication due to nitrogen overenrichment in the

Taunton River Estuary and Mount Hope Bay has reached the level of

a violation of both Massachusetts and Rhode Island water quality

standards for nutrients and aesthetics, and has also resulted in

violations     of        the   numeric      [dissolved     oxygen]       standards."

According to the City, this conclusion was the product of various

errors.

             The City first assails the EPA's use of the Critical

Indicators Report, stressing that the EPA treated the report's

"straw man" threshold levels as final and authoritative when the

report treated them as preliminary and requiring further analysis.


                                          -29-
The EPA responds that, while the report may hold those threshold

levels out as preliminary and subject to future fine-tuning, the

report's "indicators" of watershed health are not.         Indeed, as the

report explains, those indicators "form the basis of an assessment

of a system's present health."        Massachusetts Estuaries Project,

supra at 22.    Thus, the EPA explains that it was entitled to use

those indicators and apply them "to site-specific data and the

extensive scientific literature on cultural eutrophication, to

determine that the Taunton Estuary was suffering from nutrient

overenrichment."

           The EAB, for its part, upheld the EPA's use of the report

on this basis, explaining that "the use of criteria from the . . .

Critical Indicators Report to evaluate water quality is fully

consistent with the NPDES permitting regulations."         It added that

the   EPA's    ultimate   determination,    after    considering      those

indicators, that the Taunton Estuary was nutrient impaired found

further support in "the SMAST report itself, which concluded that

the Taunton Estuary experienced very high levels of nitrogen and

poor water quality due to high algal levels and oxygen depletion."

           We agree that the EPA did not use the Critical Indicators

Report improperly.    The City's objections to the EPA's reliance

on the "straw man" thresholds in the Critical Indicators Report

are   ultimately   inapposite,   as   the   EPA   relied   not   on   those


                                 -30-
thresholds, but rather on the Report's indicators in reaching its

conclusion about nutrient impairment.    Of course, had the EPA been

able to rely on threshold levels not subject to future refinement,

then its analysis may have benefitted from greater scientific

certainty.   But, it was not required to delay its decision until

such information became available, and its conclusions are not

invalid because they are the product of employing the indicators

set out in the Critical Indicators Report to analyze the SMAST

data.   "As in many science-based policymaking contexts, under the

CWA the EPA is required to exercise its judgment even in the face

of some scientific uncertainty."      Upper Blackstone, 690 F.3d at

23.   Using those indicators to determine that the Taunton Estuary

was nutrient impaired for purposes of Massachusetts's narrative

criteria, see 314 Mass. Code Regs. § 4.05(4)(b), comported with

the regulations that govern translating narrative criteria in the

absence of an official state-sanctioned methodology, see 40 C.F.R.

§ 122.44(d)(1)(vi)(A), and was not arbitrary or capricious.14


14 We encounter further evidence that the EPA did more than simply
uncritically apply those thresholds to the SMAST data in the EPA's
calculation of an acceptable total nitrogen threshold for the
Taunton River Estuary. Though the Critical Indicators Report
provides the "straw man" nitrogen concentration threshold of 0.39-
0.50 mg/l for unimpaired waters, the EPA -- finding dissolved
oxygen violations and elevated chlorophyll-a concentrations taking
place at nitrogen concentrations above 0.45 mg/l -- found that
threshold insufficiently protective and therefore, as we explain
in greater detail ahead, ultimately determined that a nitrogen
threshold of 0.45 mg/l was necessary to prevent water quality

                               -31-
          Next, the City protests that, in applying the SMAST data

to the Critical Indicators Report, the EPA "did not undertake any

analysis to demonstrate the relationship between nitrogen and

dissolved oxygen or plant growth" in the Taunton Estuary.          As a

result, the City says, the EPA failed to rule out a number of other

explanations   for   the   Taunton   Estuary's   low   concentration   of

dissolved oxygen and high concentration of chlorophyll.        The City

then points to a number of charts drawing from the SMAST data that

it submitted during the public comment period, which, it explains,

show that no relationship exists between the concentrations of

nitrogen and oxygen or between the concentrations of nitrogen and

chlorophyll.   The absence of any causal relationship, the City

presses, renders the EPA's determination that the Taunton Estuary

was nutrient impaired arbitrary and capricious.

          But, as the EAB correctly determined, the EPA did not

need to show causation -- for example, through a statistical

regression analysis -- to support its conclusion that the Taunton

Estuary was nutrient impaired.        Rather, the EPA needed only to

conclude that the further discharge of nitrogen had the "reasonable

potential to cause, or contribute to an excursion above any State

water standard."     40 C.F.R. § 122.44(d)(1)(i) (emphasis added);




standard violations.


                                 -32-
see also 314 Mass. Code Regs. § 4.05(4)(b)(1) (establishing the

numeric criterion that Class SB waters have a minimum of 5.0 mg/l

of dissolved oxygen), (5)(c) (establishing the narrative criterion

for Class SB waters that "[u]nless naturally occurring, all surface

waters shall be free from nutrients in concentrations that would

cause or contribute to impairment of existing or designated uses").

We further note that the words "contribute to" also indicate that

nitrogen need not be the sole cause of any potential violation of

a state standard, further undercutting the suggestion that the EPA

needed to prove causation.           Moreover, in upholding the "reasonable

potential" determination here, the EAB observed that under the

NPDES regulations, the permitting authority has a "significant

amount     of   flexibility     in     determining    whether      a   particular

discharge has a reasonable potential to cause an excursion above

a water quality criterion."           See also National Pollutant Discharge

Elimination System, 54 Fed. Reg. 23,868, 23,873 (June 2, 1989).

            The   City's   arguments       thus   miss     their   mark;   it   is

incorrect that the EPA needed to show a causal relationship between

high     concentrations    of    nitrogen     and    low    concentrations      of

dissolved oxygen.      The absence of an analysis of this sort from

the EPA's "reasonable potential" determination, therefore, cannot

have made that determination arbitrary or capricious.




                                       -33-
           And we also reject, as did the EAB, the City's related

contention that this "reasonable potential" determination was

erroneous because the SMAST data does not show any relationship

between   nitrogen,   chlorophyll,        and   dissolved    oxygen.      In

discussing the charts that the City continues to rely on in arguing

that no such relationship exists, the EAB first highlighted the

explanation in the response to comments that "the SMAST data were

not appropriate for the type of analysis (a stressor-response

analysis) performed by the [C]ity, and that the SMAST data were

generally insufficient to produce any statistically significant

correlations."     The    EAB   also   credited    the   EPA's   additional

observation in the response to comments that the City's selection

of certain data to include in these charts "would be expected to

produce   the   results   the   City   sought."      And    finally,   while

reemphasizing that the EPA's "reasonable potential" determination

did not rely on a stressor-response analysis of the SMAST data,

the EAB underscored that the EPA's own analysis of that data

"supported the conclusion that higher algal levels result in lower

levels of dissolved oxygen."

           Having considered, and found unpersuasive, the City's

various challenges, we hold that the EPA did not act arbitrarily

or capriciously in determining that the Taunton Estuary and Mount

Hope Bay were already nutrient impaired, such that further nitrogen


                                   -34-
discharges would have at least a "reasonable potential" to give

rise to violations of state water quality standards.

2.

              The City's next objection concerns the EPA's methodology

for determining a target nitrogen concentration that would ensure

unimpaired conditions.

              The EPA, we recall, needed to include in the permit

whatever water-quality-based limitations it found necessary to

prevent violations of state water quality standards.                   See 33

U.S.C.   §§    1311(b)(1)(C),     1341(a)(2);   40   C.F.R.   §§     122.4(d),

122.44(d)(4).           Thus,     having    determined   that        "cultural

eutrophication due to nitrogen overenrichment in the Taunton River

Estuary and Mount Hope Bay" was already resulting in violations of

the relevant Massachusetts and Rhode Island standards, the EPA

then needed to determine the amount of nitrogen that those waters

could permissibly contain without giving rise to any violations.

              To calculate that total nitrogen threshold, the EPA --

employing what is known as a "reference-based" approach -- looked

to one of the monitoring stations in the SMAST study, MHB16, that

"consistently     met   dissolved    oxygen   standards."       As    the   EPA

detailed in the response to comments, MHB16 was, among all of the

unimpaired sites in the SMAST study, the site with the highest

nitrogen concentration.         The nitrogen concentration at MHB16, 0.45


                                     -35-
mg/l, also fell within the range that the Critical Indicators

Report held out as consistent with unimpaired conditions (0.35-

0.5 mg/l).    The EPA further explained in the fact sheet that this

nitrogen     threshold     was    consistent      with    "total     nitrogen

concentrations previously found to be protective of [acceptable

dissolved    oxygen    levels]   in   other   southeastern      Massachusetts

estuaries    [which]    have   ranged   between    0.35   and    0.55   mg/l."

Mindful that all of the sites in the SMAST study with a nitrogen

concentration above 0.45 mg/l suffered from nutrient impairment,

the EPA explained in the response to comments that "there is simply

no evidence that a higher target [total nitrogen] concentration

would be sufficiently protective in the Taunton River Estuary."

The EPA therefore selected 0.45 mg/l as the target nitrogen

concentration that would serve as the basis for the effluent

limitations the permit would impose on the Facility.

             The City protests that the EPA's reliance on MHB16 was

"flawed," because MHB16 "could not be more dissimilar" from the

Taunton Estuary.       In support of this, the City points to comments

it submitted in response to the draft permit and fact sheet

averring that, among other things, MHB16 is "located in a bay not

a tidal river, 23 feet deeper than [the Taunton Estuary], subject

to dramatically different hydrodynamics because it is located in

a high velocity tidal strait, and subject to different organic


                                      -36-
loadings and sediment oxygen demands."           According to the City, the

"irrationality of using MHB16 is further underscored by the fact

that the average chlorophyll-a concentrations at MHB16 (10.5 µg/L)

were (1) essentially identical to the upper [Taunton Estuary], and

(2) well above the suggested 'good health' 'thresholds' EPA claimed

were necessary to ensure standards compliance."

             In the response to comments, however, the EPA explained

that   the   City    had   "clearly    overstate[d]      its    case    with   the

insistence that there is 'no objective resemblance between' Mount

Hope Bay and the contiguous Taunton River Estuary."                The EPA then

pointed out that, "[d]espite the hyperbole," those two bodies of

water "are in fact a series of segments of the same estuarine

system, characterized by different levels of mixing of the same

two source waters, continual exchange of waters among estuarine

segments,    the    same   sources    for    sediment,   the    same    climactic

conditions, [and] minor differences in depth range."               The EPA also

adds that the City has yet to explain how or why any of these

purported     differences     are    relevant    to   the      target   nitrogen

threshold that the EPA selected.

             The City's objection to the EPA's reliance on data from

MHB16 cannot be squared with the principle that our review of

agency action must afford deference to the scientific judgments of

the agency that Congress has tasked with carrying out the context-


                                      -37-
sensitive implementation of the CWA.         See Overton Park, 401 U.S.

at 416.      Ultimately, our recognition that "[w]here the agency

follows the proper procedures and acts with a reasonable basis,

both   its   choice   of   scientific     data    and   interpretation    and

application of that data to real world conditions are entitled to

deference,"     forecloses   the   City's        challenge   here.       Upper

Blackstone, 690 F.3d at 26.        This is especially so when the City

has not outlined with any specificity why the differences between

MHB16 and the Taunton Estuary would make the EPA's reliance on

that data indefensible.

3.

             The City's final challenge is that the EPA erred in

failing to take "existing conditions" in the Taunton Estuary into

account in fashioning the permit's nitrogen limitation.

             Having determined that a total nitrogen threshold of

0.45 mg/l was necessary to protect the Taunton Estuary from

nutrient impairment, the EPA then calculated the maximum nitrogen

load from the Taunton River watershed that the Estuary could

receive without exceeding that threshold.           After using a model to

calculate the amount of nitrogen that the Estuary would receive

from ocean inflows, the EPA concluded that the watershed's various

sources of nitrogen could discharge 2,081 lbs. per day of that

nutrient before pushing the Estuary's nitrogen concentration past


                                   -38-
the   0.45   mg/l   limit.    This   amounted   to   approximately     a   51%

reduction in total nitrogen loads from 2004-05 levels.                The EPA

then subtracted from that 2,081 lb. limit the amount of Nitrogen,

1,142 lbs., it projected would flow from non-point sources.15              This

resulted in a total maximum daily limit of 939 lbs. for the EPA to

allocate among the Estuary's various point-source dischargers of

nitrogen.

             The EPA first noted that allocating this maximum load

"equitably" among the watershed's six non-minor point-sources of

nitrogen would result in requiring each of those sources to limit

their discharges to a nitrogen concentration between 3.4 and 3.5

mg/l.16   But, the EPA then took into account that (1) "upgrades to

meet the most stringent permit limits are more cost-effective at

facilities with the highest flows and the highest proportion of

the   load   delivered   to   the   estuary;   (2)   the   Facility   is   the



15  To arrive at this number, the EPA started the average daily
nitrogen load from non-point sources during 2004-05.         Then,
"consistent with approaches in approved [total maximum daily
limits] in Massachusetts and elsewhere," the EPA reduced that
number by 20% to account for "the prevalence of regulated
[municipal] stormwater discharges, trends in agricultural uses and
population, and potential reductions in atmospheric deposition
through air quality programs."
16  The EPA did not take into account five point-sources that
discharged less than one million gallons per day, explaining that
they were "de minimis contributors for the purposes of this
analysis."


                                     -39-
watershed's    second-largest     discharger;      and     (3)   the    Facility

"discharges directly to the upper portion of the Taunton River

estuary, with no potential for uptake or attenuation of its

nitrogen discharges."       The EPA therefore found it appropriate to

assign the Facility -- which has a "design flow" of 8.4 million

gallons per day -- a permit limit of 3.0 mg/l.              The EPA assigned

the same limit on the Estuary's two other largest point-source

dischargers, belonging to the towns of Brockton and Somerset.               The

three remaining smaller facilities received a limit of 5.5 mg/l.

            The City presses that, in arriving at the final permit

limit for the Facility, the EPA relied only on the SMAST data,

which is from 2004-06, and as a result failed to take account of

the   allegedly   substantial    improvements      in    terms   of    dissolved

oxygen and algal conditions that have since taken place in the

Taunton Estuary.       Those improvements, the City says, may even have

obviated    the   need    for   any    nitrogen    limit    in   the    permit.

Specifically, the City says that the EPA failed to acknowledge the

following     recent     developments:       (1)   the   Taunton       Estuary's

temperature has decreased as a result of the closure of the nearby

Brayton Point power plant; (2) the "inputs of [total nitrogen]

have declined" in Narragansett Bay, Mount Hope Bay, and the Taunton

Estuary; (3) "organic loadings from [combined sewer overflows] to




                                      -40-
the upper and lower [Taunton Estuary] have declined; and (4) "algal

levels in [Mount Hope Bay] have declined."

              Insofar as the City challenges the facial validity of

the   SMAST    data    due    to   the    time    that    had    elapsed    since   its

collection, that argument is unavailing.                  Our standard of review,

once more, does not deputize us to second-guess the EPA's choice

of data, so long as the agency acts "with a reasonable basis" in

selecting and applying it.            Upper Blackstone, 690 F.3d at 26.             And

here, as the EAB explained, the agency had good reason for relying

on    the   SMAST   data,     which      drew    from    22   different     monitoring

stations:     the     more   recent      studies    --    such    as   that    of   the

Narragansett Bay Water Quality Network -- were "limited in terms

of location and parameters monitored and thus were insufficient to

form the basis for an alternative analysis of the Taunton Estuary."

Moreover, the EPA did not ignore that recent data, but rather found

that it was "consistent with [its] analysis of the SMAST data and

indicated continued adverse water quality impacts."                        Further, we

have recognized that "neither the CWA nor EPA regulations permit

the EPA to delay issuance of a new permit indefinitely until better

science can be developed, even where there is some uncertainty in

the existing data."          Id. at 22; see also Massachusetts v. EPA, 549

U.S. 497, 534 (2007) (explaining that the EPA cannot avoid its

statutory obligation to regulate greenhouse gases by "noting the


                                          -41-
uncertainty surrounding various features of climate change" when

"sufficient information exists to make an endangerment finding").

Thus, we think that the EPA was well-entitled to use the SMAST

data in the manner that it did here.

             Moreover, the agency's express consideration of the four

different recent developments identified by the City reinforces

our conclusion that the permit's nitrogen limit was not arbitrary

or capricious.     With regard to the Brayton Point plant, the EPA

resoundingly rejected the notion that the plant's closure should

have impacted its analysis.            First, it explained that while

operative, the plant's thermal discharges may have "contributed

incrementally to dissolved oxygen depletion in Mount Hope Bay

[but], . . . extensive modeling efforts . . . were unable to

quantify the impact of those thermal discharges on [dissolved

oxygen]   concentrations."       The    EPA   further   explained   in   the

response to comments that the impact of the plant's thermal

discharges was minimal in the Taunton River Estuary because of

that portion of Mount Hope Bay's naturally elevated temperatures.

And the EPA also noted that -- because thermal loads in the Mount

Hope   Bay   had   been   "dramatically   reduced   since   2011,"   while

dissolved oxygen depletions nonetheless persisted during that

period -- the City's theory that the plant's closure had remedied




                                   -42-
the Taunton Estuary's low dissolved oxygen levels was "unsupported

by any evidence at all."

            Turning to the City's next argument -- that the EPA

failed to consider new data indicating that total nitrogen inputs

had declined -- we note that the EAB rejected the City's claim

that the agency failed to consider "potential improvements."                    In

so doing, the EAB emphasized that in the response to comments, the

EPA explained that "while some nitrogen reductions have occurred

in   connection    with     improved     treatment       at    other   wastewater

treatment   plants     in   Massachusetts,       these    reductions     are    not

predicted   to    be   sufficient      to     achieve    the    target   nitrogen

concentration or water quality standards."

            The EPA also took up the City's submission concerning

reduced combined sewer overflows in the response to comments, but

concluded that those reductions "while important in addressing

other pressing water quality problems, are not expected to have a

significant impact on [dissolved oxygen] conditions in the upper

Taunton   River   estuary."      The     EPA    also     explained     that   those

reductions came nearly entirely from combined sewer overflows

"located more than 6 miles downstream of the station used as the

locus for the loading analysis and discharge only during wet

weather, when flows from the Taunton River are at their highest




                                       -43-
and . . . move most strongly away from the estuary." Thus, the EPA

was similarly unmoved by this objection from the City.

          Finally, while the City maintains that the EPA has

conceded that algal conditions have improved, the EPA's engagement

with that argument in the response to comments proves otherwise.

There, it explained that it disagreed with the City's comment

asserting that "[a]lgal levels in Mount Hope Bay have dropped

significantly since 2004/05" and that "[p]eak and average algal

levels are at all-time lows."      That comment, the EPA tells us,

attempted to draw "conclusions from a single year of variation[,]

2010, while 2009 was the highest year on record for average

chlorophyll-a   concentrations."       And,   the   EPA   added,   the

chlorophyll-a concentrations recorded in 2010, "while lower than

those seen in 2004-05, are still significantly higher than the

levels identified in the Critical Indicators Report as reflecting

unimpaired conditions in SB waters."    We, therefore, do not think

that the EPA's permitting decision suffers from any failure to

engage with this submission either.      The City, therefore, fails

to convince us that the EPA impermissibly relied on the SMAST data

or neglected to consider developments that post-dated that data.

          We now turn to its final contention: that, in allocating

the total daily maximum nitrogen load of 939 lbs. among point-

sources of nitrogen, the EPA ignored the "impact of the largest


                                -44-
(by far) discharger in the system" -- the City of Fall River.      The

EPA urges us to find this argument waived, the City having raised

it only after briefing before the EAB was complete, by way of an

untimely submission.    But even were we to consider this argument

on the merits, the outcome would be no better for the City.       For,

the EPA calculated the Permit's nitrogen limit based on standards

governing and conditions in the Taunton River Estuary, while Fall

River discharges only into the greater Mount Hope Bay.        And, far

from ignoring Fall River's impact on conditions in Mount Hope Bay,

the EPA explained as early as in the fact sheet that "[w]hile other

loads to Mount Hope Bay (particularly the Fall River [wastewater

treatment plant]) will need to be addressed as well, the reduction

in nitrogen loadings from the Taunton River will ensure that those

discharges   do   not   cause   or   contribute   to   nitrogen-related

impairments in Mount Hope Bay.

          Having considered all of the City's protestations to the

contrary, we find that in calculating the Permit's effluent limit,

the EPA neither relied on impermissible factors nor failed to

consider a crucial aspect of the problem, and that its explanation

for that limit neither flaunted the evidence in the record nor is

"so implausible that it could not be ascribed to a difference in

view or the product of agency expertise." Motor Vehicle Mfrs.

Ass'n, 463 U.S. at 43.     As the EPA's detailed explanation of how


                                 -45-
it calculated the permit's nitrogen limit of 3.0 mg/l reveals,

that limit falls within the "zone of reasonableness," and so we do

not see fit to second-guess it.   See Upper Blackstone, 690 F.3d

at 28; see also Solite Corp. v. EPA, 952 F.2d 473, 488 (D.C. Cir.

1991).   As a result, we leave undisturbed this well-reasoned

exercise of the EPA's delegated authority to administer the CWA.

                              III.

          None of the City's procedural or substantive challenges

having merit, the decision of the EAB is affirmed.




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