State of Michigan v. United States Army Corps of E ( 2011 )


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  •                              In the
    United States Court of
    Appeals
    For the Seventh Circuit
    No. 10-3891
    STATE OF M ICHIGAN, et al.,
    Plaintiffs-Appellants,
    and
    G RAND T RAVERSE B AND OF O TTAWA
    AND C HIPPEWA INDIANS,
    Intervenor-Appellant,
    v.
    U NITED STATES A RMY C ORPS OF
    E NGINEERS, et al.,
    Defendants-Appellees,
    and
    C ITY OF C HICAGO, et al.,
    Intervenors-Appellees.
    Appeal from the United States District Court
    for the Northern District of Illinois, Eastern Division.
    No. 10 C 4457—Robert M. Dow, Jr., Judge.
    2                                                 No. 10-3891
    A RGUED M AY 5, 2011 — D ECIDED A UGUST 24, 2011*
    Before M ANION, W OOD, and W ILLIAMS, Circuit Judges.
    W OOD, Circuit Judge. Ambitious engineering projects that
    began at the time that the City of Chicago was founded have
    established a waterway in northeastern Illinois that connects
    Lake Michigan to the Mississippi watershed. (Additional
    links between the Mississippi and the Great Lakes exist
    elsewhere, from northern Minnesota to New York.) The
    system of canals, channels, locks, and dams, with which we
    are concerned, known today as the Chicago Area Waterway
    System (or CAWS, as the parties call it in their briefs), winds
    from the mouth of the Chicago River and four other points
    on Lake Michigan to tributaries of the Mississippi River in
    Illinois. The navigable link has been a boon to industry and
    commerce, and it supports transportation and recreation.
    Public health crises that once were common because the
    Chicago River emptied the City’s sewage into the lake – the
    City’s freshwater supply – vanished thanks to the Chicago
    Sanitary and Ship Canal, which reversed the flow of the
    Chicago River so that it now pulls water from the lake, into
    the CAWS, and down toward the Mississippi. During heavy
    rains and seasonal high waters in the region, the CAWS is
    used to control flooding.
    This effort to connect the Great Lakes and Mississippi
    watersheds has not been without controversy. At the turn of
    the 20th century, Missouri sued in the Supreme Court to
    stop Illinois from opening the Sanitary and Ship Canal. An
    opinion by Justice Holmes rejected Missouri’s challenge; the
    Court concluded that the state had not presented enough
    evidence to establish that the flow of sewage toward the
    *
    This opinion is released in typescript; a printed
    version will follow.
    No. 10-3891                                                     3
    Mississippi would create a public nuisance. Missouri v.
    Illinois, 
    200 U.S. 496
     (1906); see also Missouri v. Illinois, 
    180 U.S. 208
     (1901). Several years later a broader fight erupted
    among the states bordering the Great Lakes, and the Court
    began to issue decrees setting the maximum rate at which
    Illinois may divert water away from Lake Michigan and into
    the CAWS. E.g., Wisconsin v. Illinois, 
    449 U.S. 48
     (1980);
    Wisconsin v. Illinois, 
    388 U.S. 426
     (1967); Wisconsin v. Illinois,
    
    311 U.S. 107
     (1940); Wisconsin v. Illinois, 
    278 U.S. 367
     (1929).
    Nor has opening a pathway between these bodies of fresh
    water come without costs. This appeal requires us to
    consider one of those costs: the environmental and economic
    harm posed by two invasive species of carp, commonly
    known as Asian carp, which have migrated up the
    Mississippi River and now are poised at the brink of this
    man-made path to the Great Lakes. The carp are voracious
    eaters that consume small organisms on which the entire
    food chain relies; they crowd out native species as they enter
    new environments; they reproduce at a high rate; they travel
    quickly and adapt readily; and they have a dangerous habit
    of jumping out of the water and harming people and
    property.
    In an attempt to stop the fish, Michigan, Minnesota, Ohio,
    Pennsylvania, and Wisconsin, all states bordering the Great
    Lakes, filed this lawsuit against the U.S. Army Corps of
    Engineers (the Corps) and the Metropolitan Water
    Reclamation District of Greater Chicago (the District), which
    together own and operate the facilities that make up the
    CAWS. The plaintiff states allege that the Corps and the
    District are managing the CAWS in a manner that will allow
    invasive carp to move for the first time into the Great Lakes.
    The states fear that if the fish establish a sustainable
    population there, ecological disaster and the collapse of
    billion-dollar industries that depend on the existing
    ecosystem will follow. They say that the defendants’ failure
    to close down parts of the CAWS to avert the crisis creates
    a grave risk of harm, in violation of the federal common law
    of public nuisance, see American Electric Power Co., Inc. v.
    4                                                  No. 10-3891
    Connecticut, 
    131 S. Ct. 2527
     (2011), and they advance a
    related claim against the Corps based on the Administrative
    Procedure Act (APA), 
    5 U.S.C. § 702
    . The states asked the
    district court for declaratory and injunctive relief and moved
    for a preliminary injunction that would require the
    defendants to put in place additional physical barriers
    throughout the CAWS, implement new procedures to stop
    invasive carp, and expedite a study of how best to separate
    the Mississippi and Great Lakes watersheds permanently.
    Other parties intervened to protect their interests – the
    Grand Traverse Band of Ottawa and Chippewa Indians on
    the side of the plaintiffs, and the City of Chicago, Wendella
    Sightseeing Company, and the Coalition to Save Our
    Waterways as defendants. The district court denied the
    motion for a preliminary injunction, and the states appealed
    immediately. See 
    28 U.S.C. § 1292
    (a)(1).
    We conclude that the court’s decision to deny preliminary
    relief was not an abuse of discretion. Our analysis, however,
    differs in significant respects from that of the district court,
    which was persuaded that the plaintiffs had shown only a
    minimal chance of succeeding on their claims. We are less
    sanguine about the prospects of keeping the carp at bay. In
    our view, the plaintiffs presented enough evidence at this
    preliminary stage of the case to establish a good or perhaps
    even a substantial likelihood of harm – that is, a non-trivial
    chance that the carp will invade Lake Michigan in numbers
    great enough to constitute a public nuisance. If the invasion
    comes to pass, there is little doubt that the harm to the
    plaintiff states would be irreparable. That does not mean,
    however, that they are automatically entitled to injunctive
    relief. The defendants, in collaboration with a great number
    of agencies and experts from the state and federal
    governments, have mounted a full-scale effort to stop the
    carp from reaching the Great Lakes, and this group has
    promised that additional steps will be taken in the near
    future. This effort diminishes any role that equitable relief
    would otherwise play. Although this case does not involve
    the same kind of formal legal regime that caused the
    No. 10-3891                                                      5
    Supreme Court to find displacement of the courts’ common-
    law powers in American Electric Power, on the present state
    of the record we have something close to it. In light of the
    active regulatory efforts that are ongoing, we conclude that
    an interim injunction would only get in the way. We stress,
    however, that if the agencies slip into somnolence or if the
    record reveals new information at the permanent injunction
    stage, this conclusion can be revisited.
    I
    To justify a preliminary injunction, the plaintiff states
    must show that they are likely to succeed on the merits of
    their claims, that they are likely to suffer irreparable harm
    without an injunction, that the harm they would suffer
    without the injunction is greater than the harm that
    preliminary relief would inflict on the defendants, and that
    the injunction is in the public interest. Winter v. Natural Res.
    Def. Council, Inc., 
    555 U.S. 7
    , 20 (2008). We will affirm the
    decision to deny a preliminary injunction unless the district
    court has abused its discretion. Judge v. Quinn, 
    612 F.3d 537
    ,
    557 (7th Cir. 2010). As usual, we review questions of fact for
    clear error and questions of law de novo. Girl Scouts of
    Manitou Council, Inc. v. Girl Scouts of United States of Am., Inc.,
    
    549 F.3d 1079
    , 1086-87 (7th Cir. 2008).
    II
    We begin with the states’ likelihood of succeeding on their
    common law public nuisance claim. The district court
    thought that the states had “at best, a very modest likelihood
    of success.” For the reasons discussed below, we think that
    the district court underestimated the likely merit of the
    states’ claim, particularly at this early stage of the case.
    A
    The Supreme Court recently reminded us that when it
    said, “There is no federal general common law,” in Erie
    6                                                   No. 10-3891
    Railroad Co. v. Tompkins, 
    304 U.S. 64
    , 78 (1938), it did not
    close the door on federal common law entirely. American
    Electric Power, 
    131 S. Ct. at 2535-37
    . Instead, following Erie,
    a “keener understanding” of federal common law
    developed, under which federal courts “fill in ‘statutory
    interstices,’ and, if necessary, even ‘fashion federal law’” in
    areas “‘within national legislative power.’” 
    Id. at 2535
    (quoting Henry J. Friendly, In Praise of Erie - And of the New
    Federal Common Law, 
    39 N.Y.U. L. Rev. 383
     (1964)). In
    American Electric Power, the Court reaffirmed a long line of
    cases that have “approved federal common law suits
    brought by one State to abate pollution emanating from
    another State.” 
    131 S. Ct. at 2535-36
    . These decisions reach at
    least as far back as the battle between Missouri and Illinois
    over sewage, see Missouri v. Illinois, supra, and they have
    continued from there, see Georgia v. Tennessee Copper Co., 
    206 U.S. 230
     (1907), New York v. New Jersey, 
    256 U.S. 296
     (1921),
    New Jersey v. City of New York, 
    283 U.S. 473
     (1931), Illinois v.
    City of Milwaukee, 
    406 U.S. 91
     (1972) (Milwaukee I), City of
    Milwaukee v. Illinois, 
    451 U.S. 304
     (1981) (Milwaukee II), and
    American Electric Power, 
    131 S. Ct. 2527
    . But it has been
    recognized for a much longer period that the equitable
    power of the courts extends to suits to abate public
    nuisances. See United Steelworkers of America v. United States,
    
    361 U.S. 39
    , 60-61 (1959) (Frankfurter, J., concurring)
    (assembling examples from 16th century England to the turn
    of the 20th century in the United States).
    It is our federal system that creates the need for a federal
    common law to govern interstate disputes over nuisances.
    Tennessee Copper explains that when the states joined the
    union and in so doing abandoned their right to abate foreign
    nuisances by force, “they did not thereby agree to submit to
    whatever might be done. They did not renounce the
    possibility of making reasonable demands on the ground of
    their still remaining quasi-sovereign interests; and the
    alternative to force is a suit in this court.” 
    206 U.S. at 237
    . A
    state that wants to bring a lawsuit attacking a nuisance
    emanating from outside of its borders faces at least two legal
    No. 10-3891                                                    7
    difficulties: whom to sue, and what law to apply? If the
    offender is another state, then the Constitution permits an
    original action in the Supreme Court. U.S. CONST. Art. III sec.
    2, cl. 5. Whatever the venue, applicable law is a problem: the
    offending state owes no allegiance to the law of the plaintiff
    state, but the plaintiff state may rightly fear protectionism if
    the law of the offending state is used. Committee for
    Consideration of Jones Falls Sewage Sys. v. Train, 
    539 F.2d 1006
    ,
    1008 (4th Cir. 1976) (en banc). Responding to this concern, the
    Court has concluded that in the context of interstate
    nuisances “where there is an overriding federal interest in
    the need for a uniform rule of decision or where the
    controversy touches basic interests of federalism,” federal
    common law governs. Milwaukee I, 
    406 U.S. at
    105 n.6. When
    evaluating claims based on the federal common law of
    nuisance, courts must be mindful that they do not have
    “creative power akin to that vested in Congress.” American
    Electric Power, 
    131 S. Ct. at 2536
    .
    1
    The states’ public nuisance action here is based on
    allegations that non-native species of carp (specifically,
    bighead and silver carp) will migrate through waterworks
    operated by the defendants from rivers connected to the
    Mississippi into Lake Michigan and on to the other Great
    Lakes. “When we deal with air and water in their ambient
    and interstate aspects, there is a federal common law.”
    Milwaukee I, 
    406 U.S. at 103
    . We know that this body of law
    applies in a dispute about “the pollution of a body of water
    such as Lake Michigan bounded, as it is, by four States,” 
    id.
    at 105 n.6. But the Court has cautioned that it has never
    “held that a State may sue to abate any and all manner of
    pollution originating outside its borders.” American Electric
    Power, 
    131 S. Ct. at 2536
    . The Corps and the District contend
    that the common law does not extend to the allegations in
    this case. They stress that they are not emitting “traditional
    pollutants”; all they have done, they say, is to operate
    facilities in the CAWS through which invasive species
    already living in local rivers might travel on their own. We
    8                                                    No. 10-3891
    can dismiss the latter part of this argument without much
    discussion: the defendants bear responsibility for nuisances
    caused by their operation of a manmade waterway between
    the Great Lakes and Mississippi watersheds. That they are
    not themselves physically moving fish from one body of
    water to the other does not mean that their normal operation
    of the CAWS cannot cause a nuisance. See, e.g.,
    R ESTATEMENT (SECOND) TORTS § 834 (“One is subject to
    liability for a nuisance caused by an activity, not only when
    he carries on the activity but also when he participates to a
    substantial extent in carrying it on.”) & cmt. (b) (defining
    “activity” to include acts “that create physical conditions
    that are harmful to neighboring land after the activity that
    created them has ceased”).
    Similarly, we know of no rule saying that the defendants
    must emit a “traditional pollutant” in order for federal
    common law to apply. While it may be true that the
    introduction of an invasive species of fish into a new
    ecosystem does not fit the concept of nuisance as neatly as
    a spill of toxic chemicals into a stream, we do not think the
    Supreme Court has limited the concept of public nuisance as
    much as the defendants suggest. A public nuisance is
    defined as a substantial and unreasonable interference with
    a right common to the general public, usually affecting the
    public health, safety, peace, comfort, or convenience.
    R ESTATEMENT (SECOND) T ORTS § 821B; D AN B. D OBBS, T HE
    L AW OF T ORTS § 467, at 1334 (2000). It would be arbitrary to
    conclude that this type of action extends to the harm caused
    by industrial pollution but not to the environmental and
    economic destruction caused by the introduction of an
    invasive, non-native organism into a new ecosystem
    (assuming that the states have correctly forecast the
    depletion of the Great Lakes fishery and the corresponding
    damage to the multi-billion-dollar sports fishing industry).
    Public nuisance traditionally has been understood to cover
    a tremendous range of subjects:
    It includes interferences with the public health, as in the
    case of a hogpen, the keeping of diseased animals, or a
    No. 10-3891                                                   9
    malarial pond; with the public safety, as in the case of
    the storage of explosives, the shooting of fireworks in
    the streets, harboring a vicious dog, or the practice of
    medicine by one not qualified; with public morals, as in
    the case of houses of prostitution, illegal liquor
    establishments, gambling houses, indecent exhibitions,
    bullfights, unlicensed prize fights, or public profanity;
    with the public peace, as by loud and disturbing noises,
    or an opera performance which threatens to cause a riot;
    with the public comfort, as in the case of bad odors,
    smoke, dust and vibration; with public convenience, as
    by obstructing a highway or a navigable stream, or
    creating a condition which makes travel unsafe or
    highly disagreeable, or the collection of an inconvenient
    crowd; and in addition, such unclassified offenses as
    eavesdropping on a jury, or being a common scold.
    K EETON, et al., PROSSER AND K EETON ON T ORTS § 90, at 643-45
    (5th ed. 1984) (citations omitted). The Supreme Court’s
    application of public nuisance principles to cases involving
    shared water resources reflects this broad understanding.
    For example, the Court has held that a change in one state’s
    water-drainage system that causes flooding on another
    state’s farms may create a public nuisance, see North Dakota
    v. Minnesota, 
    263 U.S. 365
    , 374 (1923); just as the industrial
    contamination of a body of water might, Arizona Copper Co.
    v. Gillespie, 
    230 U.S. 46
    , 57 (1913). In this vein, American
    Electric Power emphasized “that public nuisance law, like
    common law generally, adapts to changing scientific and
    factual circumstances.” 
    131 S. Ct. at 2536
    . The types of
    invasive carp that are the concern in this case have been
    designated as injurious species by the U.S. Fish and Wildlife
    Service, see 
    50 C.F.R. § 16.13
    (a)(2)(v); this designation means
    that it is a federal crime under the Lacy Act to transport
    them around or into the United States, 
    16 U.S.C. §§ 3371-78
    .
    We conclude that the federal common law of public
    nuisance extends to the problem that the plaintiff states have
    identified.
    2
    10                                                  No. 10-3891
    The next question, which is raised only by the Corps, is
    whether the plaintiff states may state a claim based on the
    federal common law of public nuisance against the United
    States. The Corps asserts that “the States have shown no
    basis for recognizing a federal common-law public nuisance
    claim against a federal agency.” But the Corps has not
    developed the argument much beyond this broad statement.
    Its brief moves instead to a discussion of whether federal
    common law has been displaced by congressional legislation
    and whether there is any role for the courts to play when
    agencies have taken concerted action to address a problem.
    These are two important issues that we will explore below,
    but neither point explains why a claim based on the federal
    common law of public nuisance cannot move forward
    against the United States. The plaintiff states have done little
    to counter the Corps’s suggestion. They reply
    (unresponsively, in our view) that “the federal common law
    of public nuisance undoubtedly exists.”
    The implications of finding that the United States has
    created a public nuisance strike us as potentially important
    and complex; this is not a topic that can be thrown on the
    table and then ignored. In this connection, it is telling that
    the Supreme Court went out of its way in American Electric
    Power to point out that it “ha[d] not yet decided whether
    private citizens . . . or political subdivisions . . . of a State
    may invoke the federal common law of nuisance to abate
    out-of-state pollution.” 
    131 S. Ct. at 2536
    . It declined to
    answer that question because it thought it best to resolve the
    case on other grounds. But the Court’s statement cautions us
    to tread carefully whenever we consider how far to push a
    theory of federal common law. This concern is less pressing
    for claims the Court has already recognized, such as those
    against state or local governmental entities or private
    parties. See, e.g., Missouri v. Illinois, 
    200 U.S. 496
     (states),
    Milwaukee I, 
    406 U.S. 91
     (political subdivisions); Tennessee
    Copper, 
    206 U.S. 230
     (private citizens).
    We have not discovered any case in which the Supreme
    Court has expressly authorized a public nuisance action
    No. 10-3891                                                 11
    against the United States in its sovereign capacity. A recent
    concurring opinion in the D.C. Circuit makes the same
    observation, noting that “the Court has not endorsed any
    federal common-law causes of action against the
    Government during the post-Erie period.” El-Shifa Pharm.
    Indus. Co. v. United States, 
    607 F.3d 836
    , 853 (D.C. Cir. 2010)
    (Kavanaugh, J., concurring). To understand common-law
    public nuisance in a way that would exclude suits against
    the United States would be faithful to the ancient origins of
    nuisance, where the term described the criminal act of
    infringing on the rights of the Crown, see William L. Prosser,
    Private Action for Public Nuisance, 
    52 Va. L. Rev. 997
    , 998
    (1966); at least during that era, no one would have
    contemplated that the King or Queen could be the source of
    a nuisance. Whether this sort of sovereign prerogative has
    any place in modern American law, as a concept distinct
    from the sovereign immunity of the United States, is a
    separate question. Perhaps there is also a modern
    justification for the position that the federal common law of
    public nuisance cannot operate against the government: this
    area of federal common law exists to provide a uniform rule
    for interstate disputes that will serve the national interest,
    and it may be thought illogical to say that a federal actor,
    which in theory embodies the national interest, is at the
    same time violating a judge-made concept of that same
    interest.
    On the other hand, there are respectable arguments in
    favor of applying public nuisance to the acts of federal
    agencies, depending on the activity in which the agency is
    engaged. We have moved far beyond the Divine Right of
    Kings and the concept that the Crown can do no wrong. We
    may assume that an agency’s effort to regulate private actors
    in a particular area would not give rise to a claim of public
    nuisance. But it is hard to see why the United States’s
    ownership of a dam, power plant, or other facility should
    automatically foreclose a public nuisance claim brought by
    a state for harms created by the operation of that facility. If
    the facility were located in and owned by State A and it was
    12                                                  No. 10-3891
    damaging State B, then State B would be entitled to assert a
    common-law claim against State A (or one of its
    subdivisions or private citizens). Our case offers a good
    illustration of the point: the Corps and the District together
    operate facilities that are allegedly on the verge of creating
    a nuisance in waters of the plaintiff states; why should the
    plaintiffs be able to state a claim against the District but not
    the Corps?
    The possible inconsistencies that would be created by such
    a rule may be the reason that no court has expressed concern
    about the appearance of the Tennessee Valley Authority – a
    federally owned entity that was created by Congress and
    acts like a private corporation – as a defendant in a public
    nuisance lawsuit. See American Electric Power, 
    131 S. Ct. 2527
    ;
    North Carolina ex rel. Cooper v. TVA, 
    615 F.3d 291
     (4th Cir.
    2010); North Carolina ex rel. Cooper v. TVA, 
    515 F.3d 344
     (4th
    Cir. 2008). In fact, out of all public nuisance decisions we
    have identified from either the Supreme Court or the Courts
    of Appeals that involve a federal agency as a defendant,
    none contains a whisper of discussion about whether the
    claim runs against the United States. In addition to the cases
    just mentioned, see Middlesex Cnty. Sewerage Auth. v. National
    Sea Clammers Ass’n, 
    453 U.S. 1
    , 4 & n.3 (1981) (claims against
    the Environmental Protection Agency and the Corps);
    Committee for Consideration of Jones Falls Sewage Sys., 
    539 F.2d 1006
     (claims against the EPA); Massachusetts v. U.S. Veterans
    Admin., 
    541 F.2d 119
     (1st Cir. 1976) (claims against the
    Veterans Administration). Whether the plaintiffs’ common-
    law action can proceed against the Corps is a question that
    may well require attention as this case proceeds. Given the
    parties’ cursory exposition of the issue and our ultimate
    conclusion that preliminary relief is not warranted, we find
    it unnecessary to say more at this point. (We see this as a
    question relating to the plaintiffs’ ability to state a claim; it
    does not implicate the court’s jurisdiction, and so there is
    nothing to prevent our declining to reach it.) For now, we
    will assume that the states’ federal common-law claim may
    proceed against all of the defendants.
    No. 10-3891                                                  13
    B
    The defendants argue that two additional obstacles also
    diminish the states’ likelihood of succeeding on their public
    nuisance claim. The first concerns the sovereign immunity
    of the United States. The Corps contends that even if it
    makes sense to apply public nuisance principles against the
    United States, the Corps is nevertheless not subject to suit
    because the United States has not waived its sovereign
    immunity for this kind of claim. The second argument,
    which we address below, is that congressional regulation of
    the invasive carp problem has displaced any role for federal
    common law.
    “Absent a waiver, sovereign immunity shields the Federal
    Government and its agencies from suit.” F.D.I.C. v. Meyer,
    
    510 U.S. 471
    , 475 (1994). The Corps takes the position that
    there is no such waiver of immunity for lawsuits against the
    United States that seek declaratory and injunctive relief
    based on a federal common-law tort. Whether this is correct
    depends on the interaction between section 702 of the APA
    and the Federal Tort Claims Act (FTCA), 
    28 U.S.C. § 1346
    (b).
    We begin with a look at the APA. Section 702 reads as
    follows:
    A person suffering legal wrong because of agency
    action, or adversely affected or aggrieved by agency
    action within the meaning of a relevant statute, is
    entitled to judicial review thereof. An action in a court
    of the United States seeking relief other than money
    damages and stating a claim that an agency or an officer
    or employee thereof acted or failed to act in an official
    capacity or under color of legal authority shall not be
    dismissed nor relief therein be denied on the ground
    that it is against the United States or that the United
    States is an indispensable party.
    
    5 U.S.C. § 702
    . “The first and second sentences of § 702 play
    quite different roles.” Veterans for Common Sense v. Shinseki,
    
    644 F.3d 845
    , 866 (9th Cir. 2011). The first supplies a right to
    14                                                   No. 10-3891
    seek review of agency action; the second, added by the 1976
    amendments to the statute, provides a waiver of sovereign
    immunity. 
    Id.
     The waiver covers actions that seek specific
    relief other than money damages; this aptly describes the
    plaintiffs’ claim for declaratory and injunctive relief. See
    Blagojevich v. Gates, 
    519 F.3d 370
    , 371-72 (7th Cir. 2008)
    (noting that § 702 “waived sovereign immunity for most
    forms of prospective relief”); see also Bowen v. Massachusetts,
    
    487 U.S. 879
    , 893 (1988) (construing § 702’s waiver broadly
    and remarking that “complaints [for] declaratory and
    injunctive relief . . . [are] certainly not actions for money
    damages”); Veterans for Common Sense, 644 F.3d at 864-65.
    Moreover, the waiver in § 702 is not limited to claims
    brought pursuant to the review provisions contained in the
    APA itself. The waiver applies when any federal statute
    authorizes review of agency action, as well as in cases
    involving constitutional challenges and other claims arising
    under federal law. Blagojevich, 
    519 F.3d at 372
    ; Czerkies v. U.S.
    Dep't of Labor, 
    73 F.3d 1435
    , 1437-38 (7th Cir. 1996) (en banc);
    see also Veterans for Common Sense, 644 F.3d at 867-68;
    Trudeau v. Federal Trade Comm’n, 
    456 F.3d 178
    , 186-87 (D.C.
    Cir. 2006); United States v. City of Detroit, 
    329 F.3d 515
    , 520-21
    (6th Cir. 2003) (en banc); Jaffee v. United States, 
    592 F.2d 712
    ,
    718 (3d Cir. 1979).
    Although the United States has argued from time to time
    that the “final agency action” requirement of § 704 limits the
    waiver of immunity in § 702, it has not prevailed on that
    ground. E.g., Veterans for Common Sense, 644 F.3d at 866-68;
    Trudeau, 
    456 F.3d at 186-87
    . The Corps wisely does not take
    that position here; as the Ninth Circuit explained recently,
    the conditions of § 704 affect the right of action contained in
    the first sentence of § 702, but they do not limit the waiver of
    immunity in § 702+s second sentence. Veterans for Common
    Sense, 644 F.3d at 866-68. The only limitation on § 702 that
    requires our attention is the clause that says, “Nothing
    herein . . . confers authority to grant relief if any other
    statute that grants consent to suit expressly or impliedly
    forbids the relief which is sought,” 
    5 U.S.C. § 702
    (2), which
    No. 10-3891                                                   15
    Congress added to the statute at the same time that it
    introduced the waiver of sovereign immunity, see Pub. L.
    94-574, 
    90 Stat. 2721
     (Oct. 21, 1976). Pointing to this
    provision, the Corps frames an argument by negative
    implication: it says that when Congress enacted the FTCA in
    1946, it did so against a backdrop of no tort liability for the
    United States; the FTCA waives the government’s sovereign
    immunity in suits for money damages to the extent that a
    private person would be held liable under applicable state
    tort law, see 
    28 U.S.C. § 1346
    (b)(1); Smith v. United States, 
    507 U.S. 197
    , 201-02 (1993); Parrott v. United States, 
    536 F.3d 629
    ,
    635 (7th Cir. 2008); but while the FTCA authorizes actions
    for damages, it says nothing at all about injunctive relief;
    thus, the FTCA implicitly prohibits injunctive relief in tort
    suits against the United States; and because of § 702(2), the
    Corps’s argument concludes, the plaintiffs cannot use the
    APA’s wavier of immunity to assert a common-law tort
    claim against the United States.
    That argument reads too much into congressional silence.
    The FTCA authorizes various tort claims for damages
    against the government to the extent that state law would
    provide relief, and it spells out a number of explicit
    exceptions. E.g., 
    28 U.S.C. § 2674
     (barring punitive damages
    and interest before judgment); 
    id.
     § 2680 (limiting the waiver,
    among other circumstances, where the alleged tort concerns
    the government’s enforcement of a statute or a discretionary
    function). There is nothing in the statute suggesting that
    Congress meant to forbid all actions that were not expressly
    authorized. To the contrary, section 702(2) requires evidence,
    in the form of either express language or fair implication,
    that Congress meant to forbid the relief that is sought. The
    Corps’s effort to transform silence into implicit prohibition
    would seriously undermine Congress’s effort in the APA to
    authorize specific relief against the United States. When
    Congress amended the APA in 1976 it gave every indication
    that it intended to provide specific relief for all nonstatutory
    claims against the government. See Trudeau, 
    456 F.3d at 186-87
     (noting that all the reports from Congress “identified
    16                                                  No. 10-3891
    as the measure’s clear purpose elimination of the sovereign
    immunity defense in all equitable actions” and that “the
    Senate Report plainly indicated that Congress expected the
    waiver to apply to nonstatutory actions”) (internal quotation
    marks and alterations removed); Jaffee, 
    592 F.2d at 718-19
    (outlining the reasons for the amendments to § 702, the
    concern that some executive departments were hiding
    behind their immunity, and concluding, “It was therefore
    precisely for equitable actions under section 1331 that
    Congress enacted the amendments to section 702“).
    The D.C. Circuit has read the Tucker Act, which it
    interprets as the exclusive remedy for contract claims
    against the government, to include an implicit prohibition
    against specific relief in contract actions against the United
    States and thus to prevent reliance on the APA’s waiver of
    immunity in such cases. Sharp v. Weinberger, 
    798 F.2d 1521
    ,
    1523-24 (D.C. Cir. 1986) (Scalia, J.). But the same court has
    since decided that, whatever the unspoken effect of the
    Tucker Act may be, the FTCA does not contain a comparable
    implicit ban against specific relief in tort cases against the
    government, and thus that plaintiffs in such cases may take
    advantage of the waiver in § 702 of the APA. U.S. Info.
    Agency v. Krc, 
    989 F.2d 1211
    , 1216 (D.C. Cir. 1993). To the
    same effect, we recently explained that while “[t]he tort
    claims act doesn’t authorize equitable relief . . . . the
    Administrative Procedure Act does,” and we went on to say
    that a plaintiff asserting a tort claim against a federal agency
    could take advantage of the APA to obtain equitable relief.
    Robinson v. Sherrod, 
    631 F.3d 839
    , 841 (7th Cir. 2011).
    If that were not reason enough to reject the Corps’s
    immunity defense, there is more. By its terms, the FTCA
    does not apply to any federal common-law tort claim, no
    matter what relief is sought. As the Corps itself points out,
    state tort law – not federal law – is the source of substantive
    liability under the FTCA. See Meyer, 
    510 U.S. at 478-79
    ;
    Sobitan v. Glud, 
    589 F.3d 379
    , 388-89 (7th Cir. 2009); cf. Smith,
    
    507 U.S. at 198
     (no FTCA claim for tort committed in
    Antarctica, a sovereignless entity not subject to either state
    No. 10-3891                                                    17
    law or the law of a foreign country). The states’ tort claim is
    based entirely on federal common law, and so the claim
    would not be cognizable under the FTCA in the first place.
    Meyer, 
    510 U.S. at 478
    . And if the FTCA could never apply to
    the type of claim advanced, then there is no reason to think
    that it implicitly forbids a particular type of relief for a claim
    outside its scope. For all these reasons, we conclude that the
    waiver contained in § 702 of the APA subjects the Corps to
    the plaintiffs’ common-law claims for declaratory and
    injunctive relief.
    C
    The Corps and the District next contend that congressional
    regulation has displaced as a matter of law the federal
    common law on which the states rely. The district court
    rejected this argument on the ground that Congress had not
    done enough about the threat of invasive carp to qualify for
    displacement of the federal common-law claim. The
    defendants say this was error. As they see things, it is
    enough that Congress has passed legislation to stop the carp
    and that federal and state agencies are hard at work to
    address the problem. Because the parties disagree about the
    effect of American Electric Power and the way in which the
    displacement analysis should proceed, we begin with a few
    important principles.
    The doctrine of displacement rests on the premise that
    federal common law is subject to the paramount authority of
    Congress. New Jersey v. New York, 
    283 U.S. 336
    , 348 (1931);
    see also American Electric Power, 
    131 S. Ct. at 2537
     (“[I]t is
    primarily the office of Congress, not the federal courts, to
    prescribe national policy in areas of special federal
    interest.”). “‘[W]hen Congress addresses a question
    previously governed by a decision rested on federal
    common law . . . the need for such an unusual exercise of
    law-making by federal courts disappears.’” American Electric
    Power, 
    131 S. Ct. at 2537
     (quoting Milwaukee II, 
    451 U.S. at 314
    ). Displacement focuses on the relation between Congress
    and the federal courts – it is not a doctrine that is concerned
    18                                                 No. 10-3891
    with the relation between the federal courts and the
    executive branch. This is a distinction often neglected by
    courts, as well as by the parties to this case. Whether federal
    courts can or should play a role in the face of comprehensive
    agency action is a critical issue, which we address below, but
    executive action or lack thereof does not affect the
    displacement analysis. See American Electric Power, 
    131 S. Ct. 2538
    -39 (rejecting the argument that an agency must have
    taken action before common law is displaced and explaining
    that the EPA’s outright refusal to regulate emissions would
    not create a role for federal common law because “the
    delegation [of regulatory authority from Congress to the
    agency] is what displaces federal law”); Milwaukee II, 
    451 U.S. at 317-18
    , 324 n.18 (concluding that displacement had
    occurred because “Congress . . . has occupied the field
    through the establishment of a comprehensive regulatory
    program supervised by an expert administrative agency,”
    regardless of how thoroughly the agency has implemented
    that program) (emphasis added). Congress’s decision to
    assign a particular problem to an executive agency or its
    description of an agency’s role in addressing a problem may
    be evidence of displacement, but the ebb and flow of agency
    action neither diminishes nor increases the role of federal
    common law. The important displacement question is
    whether Congress has provided a sufficient legislative
    solution to the particular interstate nuisance here to warrant
    a conclusion that this legislation has occupied the field to the
    exclusion of federal common law.
    We readily concede that Congress has not been mute on
    the subject of the carp, but that simply underscores the
    critical question: how much congressional action is enough?
    In their supplemental memoranda filed after American
    Electric Power was decided, the defendants seize upon the
    statement from the opinion that we quoted above – that “the
    delegation is what displaces federal law.” 
    131 S. Ct. at 2538
    .
    Their view is that all Congress must do to displace federal
    law is to indicate its intention to delegate a particular
    problem to an executive agency. They read American Electric
    No. 10-3891                                                 19
    Power as an enlargement of whatever displacement doctrine
    existed previously. But the defendants have taken the
    Court’s statement out of context. The Court in that passage
    was responding to an argument that an agency must have
    acted pursuant to its statutory power before federal common
    law is displaced. See 
    id. at 2538-39
    . The Court explained that
    this was not the case and that it is congressional action, not
    executive action, that guides the displacement analysis. In so
    ruling the Court did not establish a new test based solely on
    Congress’s delegation of regulatory power; it simply pointed
    out that delegation is one type of congressional action that
    is evidence of displacement. “The test for whether
    congressional legislation excludes the declaration of federal
    common law,” the Court said, “is simply whether the statute
    ‘speak[s] directly to [the] question’ at issue.” 
    Id. at 2537
    (quoting Mobil Oil Corp. v. Higginbotham, 
    436 U.S. 618
    , 625
    (1978), and citing Milwaukee II, 
    451 U.S. at 315
    , and County of
    Oneida v. Oneida Indian Nation of N.Y., 
    470 U.S. 226
    , 236-37
    (1985)). Importantly, while Congress must have spoken to
    the particular question at issue, it is not necessary for us to
    find the same manifest congressional purpose that we would
    require in an analysis of whether Congress has preempted
    state law. Id. at 2537.
    Earlier federal nuisance cases provide additional insight
    into the level of congressional action that is sufficient to
    displace federal common law. In Milwaukee I, where Illinois
    sued Milwaukee and other cities to stop them from dumping
    sewage into Lake Michigan, the Court decided that the
    federal common law of public nuisance had not been
    displaced, despite the fact that Congress had by that time
    “enacted numerous laws touching interstate waters.” 
    406 U.S. at 101-07
    . Laws that touched on the issue at hand were
    not enough, and thus the common law action could move
    forward. At the same time, however, the Court
    foreshadowed that federal legislation “may in time pre-empt
    the field of federal common law of nuisance.” 
    Id. at 107
    . Six
    months after Milwaukee I, Congress passed sweeping
    amendments to the Federal Water Pollution Control Act
    20                                                  No. 10-3891
    (FWPCA), and nine years after its first decision, the Court
    decided in Milwaukee II that those amendments displaced
    federal common law in the area. 
    451 U.S. at 317-18
    . The
    Court viewed the amended statute as “a comprehensive
    regulatory program supervised by an expert administrative
    agency,” and it noted that under that regulatory program
    “[e]very point source discharge is prohibited unless covered
    by a permit.” 
    Id. at 317-18
    . This permitting requirement
    brought every potential interstate water polluter within
    Congress’s administrative scheme; any discharge had to be
    done with the permission of the EPA or a qualifying state
    agency; and there were enforcement options available when
    polluters failed to meet the conditions of permits that had
    been issued. See 
    id. at 310-11
    .
    Most recently, American Electric Power held “that the Clean
    Air Act and the EPA actions it authorizes displace any
    federal common law right to seek abatement of
    carbon-dioxide emissions from fossil-fuel fired power
    plants.” 
    131 S. Ct. at 2537
    . The Court found it important that
    the Clean Air Act requires the EPA to identify and establish
    performance standards for all carbon-dioxide emitters; the
    statute also “provides multiple avenues for enforcement,”
    which include state agencies (operating under power
    delegated by EPA), the EPA itself, criminal proceedings
    against violators, and private enforcement in the event that
    the EPA or the states fail to regulate emissions. If the EPA
    has not acted, states and private parties may petition the
    agency for a rulemaking, after which parties have a right to
    review in federal court. 
    Id. at 2537-38
    . The Court concluded
    with the observation that “[t]he Act itself thus provides a
    means to seek limits on emissions of carbon dioxide from
    domestic power plants—the same relief the plaintiffs seek by
    invoking federal common law. We see no room for a parallel
    track.” 
    Id. at 2538
    .
    For better or for worse, congressional efforts to curb the
    migration of invasive species, and of invasive carp in
    particular, have yet to reach the level of detail one sees in the
    air or water pollution schemes. In 1990, Congress passed the
    No. 10-3891                                                 21
    Aquatic Nuisance Prevention and Control Act in an attempt
    to stop the spread of zebra mussels and other nuisance
    species. See 
    16 U.S.C. §§ 4701
     et seq. That statute established
    the Aquatic Nuisance Species Task Force and gave it the job
    of studying invasive species and implementing a program
    “to prevent introduction and dispersal of aquatic nuisance
    species” in the United States. See 
    id.
     § 4722. In 1996, the
    National Invasive Species Act amended the 1990 law and
    directed the Corps and the task force to “investigate and
    identify environmentally sound methods for preventing and
    reducing the dispersal of aquatic nuisance species between
    the Great Lakes [basin] and the Mississippi River [basin]
    through the Chicago River Ship and Sanitary Canal,”
    including any methods that could be incorporated in the
    normal operation of the CAWS. Id. § 4722(i)(3)(A). This
    mandate led to the construction of an underwater electric
    barrier in the Chicago Ship and Sanitary Canal. The barrier
    sits just upstream of the point where the CAWS empties into
    the Des Plaines River; it is designed to deter fish from
    moving in either direction through the canal. In 2003 the
    Corps, relying on the continuing authority given to the
    Secretary of the Army in 33 U.S.C. § 2309a, began
    construction of a second barrier next to the first. The barrier
    projects received an additional influx of cash from the
    District of Columbia Appropriations Act of 2005, Pub. L.
    108-335, § 345, 
    118 Stat. 1352
     (Oct. 18, 2004). In 2007,
    Congress passed the Water Resources Development Act,
    Pub. L. No. 110-114, § 3061(b)(1), 
    121 Stat. 1121
     (Nov. 8,
    2007), which allowed the Corps to upgrade its first barrier
    and officially authorized the construction of the already-in-
    progress second barrier. Finally, the Corps received more
    money to complete a third barrier as part of the American
    Reinvestment and Recovery Act of 2009.
    Sections 3061(b) and (d) of the Water Resources
    Development Act of 2007, supra, instructed the Corps to
    undertake two studies: a short-term examination of how the
    electric barrier systems might more effectively stop invasive
    species (this is the Efficacy Study, which so far consists of
    22                                                  No. 10-3891
    four interim reports, see http://www.lrc.usace.army.mil/
    AsianCarp/efficacy.htm); and a long-term study of how the
    Mississippi and Great Lakes basins might be separated on a
    more permanent basis (this is the Great Lakes and
    Mississippi River Interbasin Study or “GLMRIS,” see
    http://glmris.anl.gov). In an appropriations bill for fiscal year
    2009, Congress provided that “the Secretary of the Army
    shall implement measures recommended in the efficacy
    study, or provided in interim reports, authorized under
    section 3061 of the Water Resources Development Act of
    2007 . . . with such modifications or emergency measures as
    the Secretary of the Army determines to be appropriate, to
    prevent aquatic nuisance species from bypassing the
    Chicago Sanitary and Ship Canal Dispersal Barrier Project
    referred to in that section and to prevent aquatic nuisance
    species from dispersing into the Great Lakes.” Energy and
    Water Development and Related Agencies Appropriations
    Act 2010, Pub. L. No. 111-85, § 126, 
    123 Stat. 2845
    , 2853 (Oct.
    28, 2009). This authority – referred to informally as the
    Section 126 power — is set to expire on September 30, 2011.
    Department of Defense and Full-Year Continuing
    Appropriations Act 2011, Pub. L. No. 112-10, §§ 1101(a)(2),
    1104, 1106, 
    125 Stat. 38
    , 103 (Apr. 15, 2011). Add to these
    measures the appropriation of funds so that the Corps can
    ensure proper operation of the CAWS, e.g., Pub. L. No. 98-63,
    
    97 Stat. 301
    , 311 (July 30, 1983); Pub. L. No. 97-88 § 107, 
    95 Stat. 1135
    , 1137 (Dec. 4, 1981); Pub. L. No. 79-525, 
    60 Stat. 634
    , 636 (July 24, 1946), and one has the whole of Congress’s
    efforts to stop invasive species from moving through the
    CAWS. Recent legislative proposals targeted at halting
    invasive carp have failed in both Houses. E.g., Close All
    Routes and Prevent Asian Carp Today Act of 2010 (CARP
    ACT), H.R. 4472, S. 2946.
    Although this legislation demonstrates that Congress is
    aware of the problem of invasive species generally, and carp
    in particular, it falls far short of the mark set by the Clean
    Air Act or the Federal Water Pollution Control Act.
    Congress has not passed any substantive statute that speaks
    No. 10-3891                                                  23
    directly to the interstate nuisance about which the states are
    complaining. Most of the laws that we have summarized
    appropriate funds to the Corps for routine maintenance of
    the CAWS or for the electric barrier project. Apart from
    requiring the construction of these barriers and giving the
    Secretary of the Army temporary power to implement
    various recommendations, Congress has ordered agencies
    (or, more commonly, informal task forces composed of
    various executive actors) only to study the invasive species
    problem and propose solutions. Beyond that, neither the
    Corps nor any other agency has been empowered actively to
    regulate the problem of invasive carp, and Congress has not
    required any agency to establish a single standard to deal
    with the problem or to take any other action. The narrow
    delegation that has taken place bears little resemblance to
    the regulatory power that the EPA wields under the Clean
    Air Act. Tellingly, Congress has not provided any
    enforcement mechanism or recourse for any entity or party
    negatively affected by the carp, and there is certainly no
    recourse to the courts under the minimal scheme that has
    been established. The district court was correct that the
    current state of congressional regulation is much closer to
    the situation examined in Milwaukee I – and perhaps even
    less extensive than that – than the regimes reviewed in
    Milwaukee II or American Electric Power.
    D
    With these important preliminary questions out of the
    way, we are at last ready to consider whether the plaintiff
    states have presented enough evidence in support of their
    nuisance claim to establish that they are likely to succeed on
    the merits. The district court thought that the states failed to
    demonstrate more than a minimal chance of success. Before
    this court, the states contend that the district court
    misunderstood the elements of public nuisance. They point
    to the district judge’s statement that the tort “contemplates
    an active – or, at least, an imminent – threat of injury” as
    evidence of that error. In their view, all they must show to
    win final relief in a trial on the merits is that there is a
    24                                                 No. 10-3891
    “significant threat” that the nuisance will occur. This is a
    distinction without a difference; the district court correctly
    understood the law of public nuisance. Nonetheless, for
    different reasons we think that the district judge may have
    underestimated the states’ likelihood of success. We will
    elaborate on this point after a brief review of the governing
    law.
    1
    The district court began with the definition of public
    nuisance found in the Restatement (Second) of Torts, which has
    been a common reference point for courts considering cases
    arising under federal common law. See Connecticut v.
    American Electric Power Co., Inc., 
    582 F.3d 309
    , 351 & n.28 (2d
    Cir. 2009), rev’d on other grounds, American Electric Power, 
    131 S. Ct. 2527
     (explaining that “[t]he Restatement definition of
    public nuisance has . . . been used in . . . federal cases
    involving the federal common law of nuisance . . . and the
    Restatement principles have served as the backbone of state
    nuisance law”). The Restatement provides that “A public
    nuisance is an unreasonable interference with a right
    common to the general public,” R ESTATEMENT (SECOND) OF
    T ORTS § 821B(1), and it goes on to explain that conduct meets
    this standard when it interferes significantly with the public
    health, safety, peace, comfort, or convenience, id. §
    821B(2)(a). We described above the reasons why the federal
    common law of public nuisance is available to redress the
    type of harm that the states have alleged. And all sides agree
    that if invasive carp were to achieve a sustainable
    population in the Great Lakes, the environmental and
    economic impact would qualify as an unreasonable
    interference with a public right. As the district court noted,
    the Corps and other agencies have repeatedly and publicly
    acknowledged the seriousness of the problem. The Corps,
    for example, has said that invasive carp “have the potential
    to damage the Great Lakes and confluent large riverine
    ecosystems,” and that it regards “[t]he prevention of an
    inter-basin transfer of bighead and silver carp from the
    Illinois River to Lake Michigan [as] paramount in avoiding
    No. 10-3891                                                     25
    ecologic and economic disaster.” As a result, the central
    question on the merits of the states’ public nuisance claim
    will be whether the harm that the states have described is
    sufficiently close to occurring that the courts should order
    the defendants to take some new action that will be effective
    to abate the public nuisance. We stress at the outset an
    important point to which we will return: this question is one
    that will be resolved after a full trial on the merits, rather
    than at this preliminary stage of the case.
    A court may grant equitable relief to abate a public
    nuisance that is occurring or to stop a threatened nuisance
    from arising. See Tennessee Copper, 
    206 U.S. at 238-39
    (requiring the plaintiff to show that a defendant’s actions
    “cause and threaten damage”). In Missouri v. Illinois, 
    200 U.S. at 518
    , the Court wrote that the threatened harm underlying
    the nuisance claim “must be shown to be real and
    immediate.” We have read the Court’s cases to say that
    “[t]he elements of a claim based on the federal common law
    of nuisance are simply that the defendant is carrying on an
    activity that is causing an injury or significant threat of
    injury to some cognizable interest of the complainant,”
    Illinois v. City of Milwaukee, 
    599 F.2d 151
    , 165 (7th Cir. 1979),
    rev’d on other grounds, Milwaukee II, 
    451 U.S. 304
    . Additional
    statements about averting threatened nuisances appear in
    the Restatement, see RESTATEMENT (SECOND) T ORTS § 821B
    cmt. (i) (“[F]or damages to be awarded [in public nuisance
    cases] significant harm must have been actually incurred,
    while for an injunction harm need only be threatened and
    need not actually have been sustained at all.”); id. § 821F
    cmt. (b) (“[E]ither a public or a private nuisance may be
    enjoined because harm is threatened that would be
    significant if it occurred.”), and in other treatises, see, e.g., 5
    J. POMEROY, A T REATISE ON E QUITY JURISPRUDENCE AND
    E QUITABLE REMEDIES, § 1937 (§ 523), at 4398 (2d ed. 1919)
    (noting that while “a mere possibility of a future nuisance
    will not support an injunction,” relief will be warranted
    when “the risk of its happening is greater than a reasonable
    man would incur”).
    26                                                  No. 10-3891
    The plaintiffs believe that the district court’s “imminent
    threat” requirement is inconsistent with these principles, but
    we do not share that view. The district court reproduced
    verbatim the elements of the claim as we described them in
    Illinois v. City of Milwaukee, supra. Its discussion of
    “immediacy” did nothing more than flesh out the Court’s
    requirement of a “real and immediate” threat in public
    nuisance cases. There is no meaningful legal difference for
    purposes of the ultimate resolution of a public nuisance
    claim between a threatened nuisance that is “imminent” and
    one that is “immediate,” “significant,” “real,” an
    “unreasonable risk,” or anything similar. The job of a court
    considering the merits of a public nuisance claim is simply
    to determine whether the activity complained of is a
    nuisance and, if so, whether it is sufficiently close to
    occurring that equitable relief is necessary to prevent it from
    happening.
    2
    We part company with the district court when it comes to
    the assessment of the states’ likelihood of success on the
    merits. Here we think it critical to bear in mind the
    difference between preliminary or interim relief, on the one
    hand, and permanent relief, on the other. The principles that
    we just reviewed relate to the ultimate outcome of a public
    nuisance proceeding. This case has not yet reached that
    stage, and one consequence of its preliminary posture is that
    the states were not required to prove that they will
    ultimately win on the merits in order to secure preliminary
    relief.
    “The propriety of preliminary relief and resolution of the
    merits are of course significantly different issues.” Parents
    Involved in Cmty. Sch. v. Seattle Sch. Dist. No. 1, 
    551 U.S. 701
    ,
    721 n.10 (2007) (internal quotation marks omitted). This is
    the reason why findings made at the preliminary injunction
    stage do not bind the district court as the case progresses. Cf.
    Guaranty Bank v. Chubb Corp., 
    538 F.3d 587
    , 591 (7th Cir.
    2008). The most significant difference between the
    No. 10-3891                                                    27
    preliminary injunction phase and the merits phase is that a
    plaintiff in the former position needs only to show “a
    likelihood of success on the merits rather than actual
    success.” Amoco Prod. Co. v. Village of Gambell, 
    480 U.S. 531
    ,
    546 n.12 (1987); cf. Chathas v. Local 134 Int’l Bhd. of Elec.
    Workers, 
    233 F.3d 508
    , 513 (7th Cir. 2000) (“A plaintiff cannot
    obtain a permanent injunction merely on a showing that he
    is likely to win when and if the merits are adjudicated.”). In
    some cases, it is necessary to expedite an ultimate decision,
    and so courts sometimes consolidate the preliminary
    injunction hearing with the trial on the merits. See FED. R.
    C IV. P. 65(a)(2). But where such consolidation has not taken
    place – and it has not here – and the question is the
    propriety of preliminary relief, the Supreme Court has
    warned against “improperly equat[ing] ‘likelihood of
    success’ with ‘success’ . . . .” University of Texas v. Camenisch,
    
    451 U.S. 390
    , 394 (1981); see also Meridian Mut. Ins. Co. v.
    Meridian Ins. Group, Inc., 
    128 F.3d 1111
    , 1119 (7th Cir. 1997).
    This is in keeping with the often-repeated rule that the
    threshold for establishing likelihood of success is low. E.g.,
    Cooper v. Salazar, 
    196 F.3d 809
    , 813 (7th Cir. 1999); Brunswick
    Corp. v. Jones, 
    784 F.2d 271
    , 275 (7th Cir. 1986).
    We are concerned that the district court here may have
    lost sight of this distinction. By applying directly the law of
    public nuisance, the judge seems to have required the
    plaintiff states actually to show that they were entitled to
    permanent injunctive relief during the preliminary
    injunction hearing. The court concluded its discussion of the
    threat posed by invasive carp, for example, by saying that
    the states “ha[d] not made a convincing case” that the fish
    had pushed into the CAWS in significant numbers; and it
    said that the plaintiffs had not “shown that the fish [are]
    anywhere near . . . establishing a population in Lake
    Michigan.” Because the states had not yet shown that the
    threat of nuisance was great enough in the final analysis to
    warrant an injunction to abate it, the district court seems to
    have assumed that they had also failed to show enough to
    obtain preliminary relief. To demonstrate the requisite
    28                                                 No. 10-3891
    likelihood of success, however, the states needed only to
    present a claim plausible enough that (if the other
    preliminary injunction factors cut in their favor) the entry of
    a preliminary injunction would be an appropriate step. The
    preliminary injunction, after all, is often seen as a way to
    maintain the status quo until merits issues can be resolved at
    trial. By moving too quickly to the underlying merits, the
    district court required too much of the plaintiffs and,
    correspondingly, gave too little weight to the strength of
    their claim at this stage of the case.
    3
    We also question the inferences drawn by the district court
    from the facts that it so carefully found after evaluating five
    days of hearings, which included the testimony of expert
    witnesses and volumes of written materials on complex
    scientific and engineering issues. There is very little to
    criticize about the court’s factual findings themselves. For
    instance, the district judge’s decision to admit the expert
    testimony of Dr. David Lodge, who has been hired by the
    Corps and who testified for the states at the preliminary
    injunction hearing about his efforts to track invasive carp
    through the use of environmental DNA (eDNA) testing,
    reflects a proper application of Federal Rule of Evidence 702.
    (We agree that any lack of peer review of Dr. Lodge’s work
    would go to the weight of his testimony, not to the court’s
    ability to consider it. Moreover, the situation will be
    different at the merits phase, given Dr. Lodge’s recent
    publication of his research. See Christopher L. Jerde,
    Andrew R. Mahon, W. Lindsay Chadderton & David M.
    Lodge, “Sight Unseen” Detection of Rare Aquatic Species Using
    Environmental DNA, 4 Conservation Letters 150 (April/May
    2011).) We also see nothing to criticize in the district court’s
    assessment that the electric barriers built by the Corps near
    the intersection of the Chicago Sanitary and Ship Canal and
    the Des Plaines River seem to have at least some deterrent
    effect on the movement of invasive carp toward the Great
    Lakes. In addition, we consider it significant, as the district
    judge did, that efforts to detect carp by techniques including
    No. 10-3891                                                29
    netting, so-called electrofishing, and rotenone poisoning,
    have led to few signs of the carp.
    Along the same lines, the district court was right to take
    into account the results of eDNA testing. Despite its
    skepticism about the reliability of the technique and its
    concern that the state of eDNA science “did not permit a
    reasonable inference that live Asian carp are in the [CAWS]
    . . . in numbers that present an imminent threat,” the court
    acknowledged that the eDNA evidence lent some support to
    the conclusion that there may be invasive carp above (i.e.
    lakeside of) the Corps’s electric barriers. Although we are
    less skeptical of the science than the district court, we too
    believe that caution in drawing inferences from the existence
    of carp DNA in the water is warranted. The eDNA
    technique, which tests water samples for markers matching
    a particular species, has a number of shortcomings: it is
    difficult, if not impossible, to know definitively whether a
    positive result signals a living specimen above the barrier
    (DNA may be shed by a dead or distant fish); a positive test
    does not reveal the number of live fish; and negative results
    do not necessarily signal the absence of carp. Efforts to
    corroborate eDNA results with traditional methods of
    capturing fish have not been successful thus far. On the
    other hand, the evidence is worth something. The eDNA
    technique detects carp when the fish are present in small
    numbers and in situations where the other fishing methods
    we described above might scare them away or simply miss
    them, and the large number of negative test results make
    sense given the sensitivity of the technique. In addition, the
    Corps and other agencies have voted with their feet: they
    have been using eDNA tests to manage the invasive carp
    crisis, and they have said that this testing will continue.
    (This is undoubtedly why the private intervenor-defendants
    are the primary critics of this methodology.) If the tests are
    good enough for expert agencies, it is hard to see why we
    should flatly forbid their consideration. A January 2011
    report on eDNA sampling conducted in 2010 showed
    positive eDNA results in approximately a dozen locations
    30                                                  No. 10-3891
    throughout the CAWS, and experts have opined that these
    results indicate the presence of carp at multiple locations in
    the CAWS. On July 29, 2011, federal officials announced that
    they would begin daily efforts to find invasive carp around
    Lake Calumet, after multiple rounds of testing revealed carp
    DNA in that area. See Asian Carp Regional Coordinating
    Com m ittee, Press Release, July 29, 2011,
    http://asiancarp.org/news/asian-carp-regional-coordinating-
    committee-to-begin-intensive-monitoring-in-lake-calumet-
    in-response-to-environmental-dna-results; Tammy Webber,
    Feds to Step Up Hunt for Asian Carp Near Chicago, Chicago
    Tribune, July 29, 2011. The district court thought that this
    evidence, in combination with the discovery of two invasive
    carp specimens (one dead and one living) in the CAWS,
    supported a theory that invasive carp are present in the
    CAWS in “low numbers.” This conclusion was reasonable.
    The carp may even be present in greater numbers, but for
    present purposes we do not need any more precision.
    Our greatest hesitation with respect to the district court’s
    findings is over its conclusion that “it is far from certain that
    Asian carp can survive and reproduce in the Great Lakes.”
    Given the record that was before Judge Dow, this prediction
    may have been sound at the time he ruled. The situation has
    been evolving rapidly since the preliminary injunction
    hearing, however, and so we think it worth mentioning that
    the newest publicly available evidence suggests that when
    and if the time comes, the carp are unlikely to have trouble
    establishing themselves in the Great Lakes. Before the
    district court there was testimony reflecting great
    uncertainty about how easily the carp could live and
    reproduce in this new habitat. A species typically requires
    multiple introductions before it takes root in a new
    ecosystem, and there has been a substantial debate, reflected
    in the literature, about whether the food supply and other
    features of the Great Lakes could support the carp. See
    generally Sandral L. Cooke & Walter R. Hill, Can Filter-
    Feeding Asian Carp Invade the Laurentian Great Lakes? A
    Bioenergetic Modelling Exercise, 55 Freshwater Biology 2138
    No. 10-3891                                                   31
    (2010); Cynthia S. Kolar & David M. Lodge, Ecological
    Predictions and Risk Assessment for Alien Fishes in North
    America, 298 Science 1233 (2002). On April 28, 2011, however,
    the Obama Administration presented two pieces of what it
    called “bad news” at a meeting in Chicago on invasive carp:
    first, it said that while it was once thought that the carp
    could not establish breeding populations in Lake Michigan
    because of the low levels of plankton (the carp’s normal food
    source) in the water, new evidence suggests that the fish will
    happily switch from eating plankton to consuming the green
    algae that now covers the lake floor (thanks to another
    invasive species, the zebra mussel); and (2) while experts
    had thought the carp need coastal rivers between 30 and 60
    miles long to spawn, it turns out they can make do with
    much shorter breeding grounds. See, e.g., Asian Carp Possibly
    Hardier than Once Thought, Chicago Tribune, Apr. 28, 2011.
    At this point, therefore, we must assume that once in the
    Great Lakes, the invasive carp would make it their home.
    We need not explore the factual record further. As we
    have said, our review of the district court’s findings is
    deferential, and we see nothing that demands correction.
    The critical point is that this record is not a static thing. The
    district court will undoubtedly have more evidence before
    it when it is time to rule on the request for a permanent
    injunction, and we are confident that the court will keep its
    mind open to the implications of any new information. For
    purposes of assessing the need for preliminary relief, the
    court relied on its findings that at best a limited number of
    invasive carp were present in the CAWS and its observation
    that the so-called invasion front was approximately 30 miles
    downstream of the CAWS (60 miles from Lake Michigan) as
    of the spring of 2009. On this basis, it reached the conclusion
    that while the potential for damage to the Great Lakes is
    high, the problem had not advanced far enough to present
    a threat to the plaintiff states. From that it drew the
    conclusion that the states had shown little likelihood of
    success on the merits.
    It is that final step that gives us trouble. As the district
    32                                                             No. 10-3891
    court rightly noted, the magnitude of the potential harm
    here is tremendous, and the risk that this harm will come to
    pass may be growing with every passing day. (It certainly
    has grown since the ill-fated day around 1970 when the carp
    escaped from various aquaculture facilities and began their
    march up the Mississippi River. See generally Wisconsin
    Dep’t of Nat. Res., Bighead and Silver Carp
    ( H y p o p h t h a l m i c h t h y s n o bi l i s a n d H . m o l i t r ix ) ,
    http://dnr.wi.gov/invasives/fact/asian_carp.htm.) Given the
    magnitude of the harm, we are inclined to give the benefit of
    the doubt to the states on the question whether they have
    shown enough of a risk of nuisance to satisfy the likelihood-
    of-success requirement at this preliminary stage. See Van De
    Sande v. Van De Sande, 
    431 F.3d 567
    , 570 (7th Cir. 2005) (“The
    gravity of a risk involves not only the probability of harm,
    but also the magnitude of the harm if the probability
    materializes.”) (citing United States v. Carroll Towing Co., 
    159 F.2d 169
    , 173 (2d Cir. 1947)). In addition, the nature of the
    threat – an ecological harm – suggests that a broader
    perspective on the problem might be necessary. It is hard to
    see 60 miles of separation between the carp invasion front
    and the Great Lakes (and remember this was the estimated
    distance more than two years ago) as a particularly safe
    margin, even with functioning electric barriers to deter fish
    and efforts to reduce propagule pressure (the volume of
    invasive carp in the water downstream of the front). It is
    especially chilling to recall that in just 40 years the fish have
    migrated all the way from the lower Mississippi River to
    within striking distance of the lakes and have come to
    dominate the ecosystem in the process. Commercial
    harvesting of carp in the Mississippi basin increased from
    just over five tons to 55 tons in the three-year period from
    1994 to 1997; there is evidence that by 1999 invasive carp
    made up 97% of the Mississippi’s biomass; and as of 2007
    commercial fishers were catching 12 tons of invasive carp
    each day. These numbers are sobering even apart from the
    hints that some of the fish may have made it into the CAWS
    already.
    No. 10-3891                                                    33
    In our view, the proper inference to draw from the
    evidence is that invasive carp are knocking on the door to
    the Great Lakes. We need not wait to see fish being pulled
    from the mouth of the Chicago River every day before
    concluding that a threat of a nuisance exists. It is enough
    that the threat is substantial and that it may be increasing
    with each day that passes. Unlike many nuisances that can
    be eliminated after they are discovered, this one in all
    likelihood cannot be. The fact that it would be impossible to
    un-ring the bell in this case is another reason to be more
    open to a conclusion that the threat is real. In our view, the
    plaintiff states presented enough evidence to establish a
    good or even substantial likelihood of success on the merits
    of their public nuisance claim.
    III
    Before moving on to the other preliminary injunction
    factors, there are some particular questions about the APA
    claim against the Corps that we must address. We turn
    again to § 702 of the APA, which authorizes a suit by “[a]
    person suffering legal wrong because of agency action, or
    adversely affected or aggrieved by agency action within the
    meaning of a relevant statute.” 
    5 U.S.C. § 702
    . A reviewing
    court is required to “compel agency action unlawfully
    withheld or unseasonably delayed,” 
    5 U.S.C. § 706
    (1), and to
    “set aside agency action . . . found to be . . . arbitrary,
    capricious, an abuse of discretion, or otherwise not in
    accordance with law,” 
    id.
     § 706(2)(A). The states do not ask
    us to compel the Corps to take action, at least as far as §
    706(1) is concerned. Norton v. Southern Utah Wilderness
    Alliance, 
    542 U.S. 55
    , 64 (2004), explains that “a claim under
    § 706(1) can proceed only where a plaintiff asserts that an
    agency failed to take a discrete agency action that it is required
    to take”; the states have named no action that they think the
    agency is required to take. We understand the states’
    argument as a request to set aside agency action that they
    regard as unlawful within the meaning of § 706(2)(A).
    34                                                   No. 10-3891
    The obvious starting point is to identify the final Corps
    action that the states assert has affected them. See 
    5 U.S.C. § 704
    ; Lujan v. National Wildlife Fed’n, 
    497 U.S. 871
    , 882 (1990).
    The states contend that five such actions fit the bill. They say
    that the Corps’s (1) operation of the CAWS in a manner that
    will let invasive carp into Lake Michigan, (2) reliance on
    ineffective electric barriers, (3) use of locks in areas where
    living and dead carp have been found, (4) denial of the
    states’ requests for additional relief, and (5) implementation
    of recommendations contained in the Corps’s third interim
    report (which is part of the Efficacy Study we discussed in
    connection with our analysis of displacement, supra) are all
    final agency actions. The district court equivocated on the
    issue, but it seems to have agreed with the states in the end.
    There is a good chance that most of the “actions” named
    by the states are not “final agency actions” for purposes of
    the APA. “Agency action” is defined as “the whole or a part
    of an agency rule, order, license, sanction, relief or the
    equivalent or denial thereof, or failure to act,” 
    5 U.S.C. § 551
    (13). The Supreme Court has explained that these
    categories all “involve circumscribed, discrete agency
    actions,” Norton, 
    542 U.S. at 62
    . Agency action is “final”
    when it marks the consummation of the agency’s
    decisionmaking process and determines legal rights or
    obligations. Bennett v. Spear, 
    520 U.S. 154
    , 177-78 (1997); see
    also Western Illinois Home Health Care, Inc. v. Herman, 
    150 F.3d 659
    , 662 (7th Cir. 1998) (citing Franklin v. Massachusetts,
    
    505 U.S. 788
     (1992), for the proposition that “[t]he core
    question is whether the agency has completed its
    decisionmaking process, and whether the result of that
    process is one that will directly affect the parties”). Applying
    these standards, we cannot see why any of the “actions” that
    are numbered 1 through 4 on the states’ list of complaints
    above should be considered final agency action. Most of the
    four “actions” are not discrete at all; and those that might be
    so classified do not represent the final outcome of any
    decisionmaking process by the Corps. The Corps’s effort to
    implement its third interim report – which recommended
    No. 10-3891                                                   35
    the installation of screens over two gates that control water
    flow between the CAWS and Lake Michigan but which
    otherwise called for normal operation of lake-facing locks –
    is the only activity that may be suitable for an APA
    challenge. We need not evaluate that claim in any detail,
    however, because it is part of the states’ larger request for
    relief based on the common law of public nuisance.
    Two types of plaintiffs are given a right of review in § 702:
    those suffering a “legal wrong,” and those “adversely
    affected or aggrieved by agency action within the meaning
    of a relevant statute.” In their briefs in this court, the states
    have not pointed to a single statute against which one might
    judge the Corps’s behavior. (This is not surprising, given the
    dearth of pertinent federal legislation that we discussed in
    connection with displacement.) The Corps submits that this
    means that the states have no APA claim; the states respond
    their APA claim is “free-standing.” Neither answer is
    satisfactory. We know that the states have not alleged that
    the Corps’s actions failed to comply with some statutory
    provision, and so they must instead be asserting that they
    have suffered a “legal wrong” because of those actions. The
    only legal wrong that comes to mind, however, is the
    infliction of a common-law public nuisance. See Lujan, 
    497 U.S. at 883
     (distinguishing between legal wrongs and the
    failure of an agency to comply with a statutory provision);
    Tennessee Electric Power Co. v. Tennessee Valley Authority, 
    306 U.S. 118
    , 137 (1939) (explaining that “legal wrong” includes
    tortious invasions and interferences with property and
    contractual rights). See generally Antonin Scalia, The
    Doctrine of Standing as an Essential Element of the Separation of
    Powers, 17 SUFFOLK U. L. REV. 881, 887-890 (1983) (discussing
    the use of the term “legal wrong” in the APA and explaining
    that it “could only mean a wrong already cognizable in the
    courts”). The result is that the states’ APA claim against the
    Corps sinks or swims (so to speak) with its public nuisance
    theory. Because they are indistinguishable, we address only
    the latter from this point on.
    36                                                  No. 10-3891
    IV
    To satisfy the second threshold requirement for
    preliminary injunctive relief, the states must establish that
    irreparable harm is likely without an injunction. Judge v.
    Quinn, 
    612 F.3d 537
    , 557 (7th Cir. 2010). In the district court’s
    view, this issue was the same as the question whether the
    states had shown a likelihood of success on the merits of
    their public nuisance claim. The states contend that it was
    error to conflate these inquiries. They are right. In this case,
    for example, the likelihood of success on the merits focuses
    on the threat of a nuisance, while the irreparable harm is
    concerned with the ability to correct that nuisance if it is
    created. Not every nuisance will give rise to irreparable
    harm. These two steps of the preliminary injunction analysis
    thus play different roles. The likelihood of success on the
    merits is an early measurement of the quality of the
    underlying lawsuit, while the likelihood of irreparable harm
    takes into account how urgent the need for equitable relief
    really is. Typically, these lines of inquiry will have some
    overlap, but they should not be treated as the same. With
    that in mind, we realize that the same evidence will inform
    both steps of the preliminary injunction analysis in this case.
    As long as the distinctions we have just mentioned remain
    clear, there is no harm in analyzing all of the evidence once
    rather than twice. As a result, the states’ criticism of the
    district court is largely academic and provides no reason to
    reverse that court’s decision.
    Putting theory to one side, we have very little trouble
    concluding that the environmental and economic harm that
    the states have shown might come to pass would be
    genuinely irreparable if it did occur. The district court
    implied that this was the case when it discussed the
    magnitude of the potential harm. Last year in Supreme
    Court filings related to this litigation, the United States
    explained in a memorandum that it agreed with Michigan
    “that allowing a reproducing population of Asian carp to
    establish itself in Lake Michigan likely would be an
    irreparable injury.” Memorandum in Opposition of the
    No. 10-3891                                                   37
    United States, at 43, Original Nos. 1, 2, and 3,
    http://w w w .suprem ecourt.gov/SpecM astRpt/U S_
    Memorandum_in_Opposition.pdf; see also id. at 47 (calling
    the harm “grave and irreparable”). All of the other parties
    seem to agree with this view. (To the extent that the
    defendants argue that there is no irreparable harm because
    the carp cannot establish a breeding population in Lake
    Michigan, they are avoiding the key question: what if the
    fish did establish a successful breeding group?) This near-
    unanimity on the question of irreparable injury makes sense.
    “Environmental injury, by its nature, can seldom be
    adequately remedied by money damages and is often
    permanent or at least of long duration, i.e., irreparable.”
    Amoco Prod., 
    480 U.S. at 545
    ; Sierra Club v. Franklin County
    Power of Illinois, LLC, 
    546 F.3d 918
    , 936 (7th Cir. 2008). Harms
    like those the states allege here are irreparable because they
    are difficult – if not impossible – to reverse. See Hollingsworth
    v. Perry, 
    130 S. Ct. 705
    , 712 (2010) (per curiam).
    For preliminary relief to be granted, the irreparable harm
    must also be likely. That is, there must be more than a mere
    possibility that the harm will come to pass, Winter, 
    555 U.S. at 21-23
    , but the alleged harm need not be occurring or be
    certain to occur before a court may grant relief, United States
    v. W.T. Grant Co., 
    345 U.S. 629
    , 633 (1953); United States v.
    Oregon State Med. Soc’y, 
    343 U.S. 326
    , 333 (1952); Bath Indus.,
    Inc. v. Blot, 
    427 F.2d 97
    , 111 (7th Cir. 1970). Commentators
    describe the required level of certainty this way: “[A]
    preliminary injunction will not be issued simply to prevent
    the possibility of some remote future injury. A presently
    existing actual threat must be shown. However, the injury
    need not have been inflicted when application is made or be
    certain to occur.” 11A C HARLES A LAN W RIGHT, ET AL.,
    FEDERAL PRACTICE AND PROCEDURE § 2948.1, at 154-55 (2d ed.
    1995). Because the district court analyzed likelihood of
    success on the merits at the same time as it assessed the
    danger of irreparable harm, all of the reservations we had
    about the inferences drawn by the district court in the
    former context apply with equal force here.
    38                                                   No. 10-3891
    As we have already pointed out, no one knows whether
    this irreparable harm will come to pass. The intense factual
    dispute we are witnessing here about the rate at which
    invasive carp are progressing makes evaluating its
    likelihood even more tricky. In our view, the district court
    required a level of proof too close to certainty when it
    assessed the danger of invasive carp escaping into Lake
    Michigan. Given the dire nature of the harm posed by the
    carp and their close proximity to the CAWS, we again will
    give the plaintiff states the benefit of the doubt. Just as they
    produced enough evidence to establish a likelihood of
    success on the merits warranting injunctive relief, so too
    have they shown, to the degree necessary for preliminary
    relief, that it is likely that irreparable harm will come to pass.
    This sets the stage for the dispositive issue: how must the
    harms the states have identified be balanced against those
    that the defendants will suffer should an injunction be
    granted?
    V
    The balancing process to which we now turn is a classic
    part of any preliminary injunction inquiry. See Winter, 
    555 U.S. at 24
     (“A preliminary injunction is an extraordinary
    remedy never awarded as of right. In each case, courts must
    balance the competing claims of injury and must consider
    the effect on each party of the granting or withholding of the
    requested relief.”) (internal quotation marks and citations
    omitted). How much of the danger forecast by the states
    would be avoided by the particular injunction they have
    asked for? And what harm would the injunction impose on
    the defendants? Typically, after we balance these party-
    specific equities, we evaluate whether the injunction would
    advance or impede the public interest. See, e.g., Ferrell v. U.S.
    Dep't of Hous. and Urban Dev., 
    186 F.3d 805
    , 811 (7th Cir.
    1999). That additional analysis is not necessary in this case,
    however, because the parties themselves, with the exception
    of two intervenors, are governmental entities that represent
    No. 10-3891                                                 39
    the interests of the public.
    When it appears that preliminary relief may be
    burdensome, the Supreme Court has instructed courts to be
    careful as they balance the competing interests. Winter, 
    555 U.S. at 27
    ; see also Kartman v. State Farm Mut. Auto. Ins. Co.,
    
    634 F.3d 883
    , 892 (7th Cir. 2011). In light of the multifarious
    ideas the states have for an injunction in this case, there can
    be no doubt that caution must be our word of the day. Even
    if a plaintiff’s suit appears to have merit, an injunction
    should not necessarily issue if the harm to the defendant
    would substantially outweigh the benefit to the plaintiff.
    MacDonald v. Chicago Park Dist., 
    132 F.3d 355
    , 357 (7th Cir.
    1997).
    In the end we conclude that a preliminary injunction
    would cause significantly more harm that it would prevent.
    We reach this result for two reasons, which we summarize
    here before explaining the balance of harms in more detail.
    First, there are a number of problems with various line items
    in the plaintiffs’ proposed package of relief. Taken together,
    these problems leave us doubting whether the proposed
    injunction would reduce by a significant amount the risk
    that invasive carp will gain a foothold in the Great Lakes
    between now and the time that a full trial on the merits is
    completed. It is clear, on the other side, that the requested
    measures would impose substantial costs on the defendants
    and the public interests they represent, as well as added
    expenses for commerce, recreation, and tourism. Second, as
    circumstances currently stand, there is a more fundamental
    reason that the states’ requested injunction is unlikely to
    prevent much harm and actually may impose costs. The
    courts would not be acting alone. As we have explained,
    there is a powerful array of expert federal and state actors
    that are engaged in a monumental effort to stop invasive
    carp from entering the Great Lakes. The last thing we need
    is an injunction operating at cross-purposes with their
    efforts or imposing needless transactional costs that divert
    scarce resources from science to bureaucracy. Furthermore,
    from an institutional perspective courts are comparatively
    40                                                  No. 10-3891
    ill situated to solve this type of problem. The balance of
    harms favors the defendants and the public interests they
    represent to such an extent that we conclude that the district
    court’s decision to deny preliminary relief was not an abuse
    of discretion.
    A
    1
    It is best to begin by trying to understand precisely what
    preliminary relief the states would like. As the district court
    noted, their request has evolved as the case has moved
    forward. Indeed, their position has shifted even between
    their opening brief in this court and oral argument. The
    moving nature of the target complicates our job of
    evaluating the propriety of injunctive relief. Moreover, their
    request has been phrased at a high level of generality. They
    have given us the broad strokes of additional steps they
    would like us to order the defendants to take, but they have
    not furnished many details about how this relief would be
    implemented, on what schedule, at what cost, and on whose
    nickel. From time to time the states urge that the injunctive
    measures should be “consistent with public health and
    safety,” but they do not say what precisely that means. This
    vagueness is unhelpful; it stands as an obstacle to the entry
    of an injunction that will satisfy Federal Rule of Civil
    Procedure 65(d). See PMC, Inc. v. Sherwin-Williams Co., 
    151 F.3d 610
    , 619-20 (7th Cir. 1998); see also Patriot Homes, Inc. v.
    Forest River Hous., Inc., 
    512 F.3d 412
    , 414-15 (7th Cir. 2008).
    When a plaintiff seeks relief of the type the states ask for
    here, we have required a more specific plan about the
    measures to be taken and the costs of implementing those
    measures. See Jordan v. Wolke, 
    593 F.2d 772
    , 774-75 (7th Cir.
    1978).
    At this time, it is our understanding that the states believe
    that they are entitled to a preliminary injunction that would
    require the defendants to take these five steps:
    a. Closing the Locks. Close and stop operating the locks at
    No. 10-3891                                                 41
    the Chicago River Controlling Works (the Controlling
    Works) and the O’Brien Lock and Dam (O’Brien), which
    sit at two of the five points of contact between the CAWS
    and Lake Michigan;
    b. Screens over Sluice Gates. Install nine additional screens
    over sluice gates that are used to control water flow
    between the CAWS and the lake at the Controlling Works,
    O’Brien, and the Wilmette Pumping Station, a third
    contact point with Lake Michigan;
    c. Block Nets in the Rivers. Place block nets to stop fish in
    the Little Calumet River, which connects the CAWS to the
    lake at the Burns Small Boat Harbor in Indiana, and if
    necessary in the Grand Calumet River, which runs
    between the CAWS and the Indiana Harbor and Canal
    (Burns Harbor and Indiana Harbor are last of the five
    contact points between the CAWS and Lake Michigan);
    d. Rotenone Poisoning. Use rotenone to poison fish in the
    CAWS, especially in areas north of O’Brien.
    e. Accelerating GLMRIS. Finish the part of the Great Lakes
    and Mississippi River Interbasin Study that relates to the
    CAWS, which Congress called for in the Water Resources
    Development Act of 2007, within 18 months.
    The states have made two additional requests that do not
    require discussion. They say that the defendants should use
    the best methods to stop, capture, and kill carp that are
    present in the CAWS. We see this as a more general
    statement of the specific measures we have just outlined. In
    addition, the states want the defendants to continue using
    monitoring techniques, including eDNA testing, to search
    for invasive carp. But the Corps and the other agencies
    working on this problem are continuing eDNA monitoring
    efforts. In July 2011, for example, three rounds of positive
    eDNA testing results led to a four-day hunt for invasive carp
    (none was found). This request asks for steps already being
    taken, and so we will not discuss it further.
    2
    42                                                No. 10-3891
    Before we discuss the harm and benefit of the preliminary
    relief the states request, we must point out an error in the
    states’ view of how the harms should be weighed. The states
    say that any harm the defendants might suffer because of
    the injunction pales “in comparison to the grave and truly
    irreparable harm that will occur if Asian carp establish a
    breeding population in the Great Lakes.” But that is not the
    correct measure of the harm avoided by the states’ proposed
    injunction. The states assume, without providing much
    explanation, that preliminary relief would stop invasive carp
    from ever reaching the Great Lakes. While that may be the
    effect that a perfectly designed permanent injunction would
    have, it is not an accurate measure of the harm that would
    be avoided by the states’ proposed preliminary injunction.
    At this early point, the question is to what extent would the
    proposed measures decrease the risk of invasive carp
    establishing themselves in the Great Lakes between now and
    when the litigation concludes? Stepping back from the
    subject matter of this litigation, we note that in addition to
    the CAWS, the Corps has identified a total of 18 places in
    Minnesota, Wisconsin, Indiana, Ohio, and New York where
    invasive carp could move from the Mississippi basin into the
    Great Lakes. These pathways outside of the CAWS
    necessarily reduce the likelihood that the states’ preliminary
    injunction will prevent carp from establishing themselves in
    the Great Lakes, because the states’ proposed measures say
    nothing about these alternate routes. Even focusing
    exclusively on the CAWS, the states overlook similar
    limitations inherent in the steps they are proposing –
    limitations that would reduce the effectiveness of
    preliminary relief, as we now explain.
    a. Closing the Locks. If the locks at the CRCW and O’Brien
    are closed, the states concede that the closure need not be
    permanent or unqualified; instead, they say, the locks may
    be opened if closure would put public health or safety at
    risk. We are not sure how that would work. The City of
    Chicago says that police and fire services use the locks
    routinely, as do Coast Guard boats. At one point, the states
    No. 10-3891                                                 43
    agreed that passage for emergency boats through the locks
    was needed for public safety. That sounds reasonable to us.
    Now, however, their injunction would allow the defendants
    to open the locks only when the District needs to release
    water from the CAWS into the lake to control flooding
    (during so-called “reversal” operations). The states’
    proposed injunction is made more effective by keeping the
    locks closed to all boat traffic, but in so doing, it increases
    the cost to emergency services. Even in its current iteration,
    the efficacy of the states’ plan for closing the locks is
    compromised because any flooding that would require the
    defendants to conduct reversal operations decreases the
    chances that the carp will be stopped – when the locks are
    open, water pours out of the CAWS and into Lake Michigan.
    (This happened most recently on July 24, 2011, after nearly
    seven inches of rain fell in only two hours, see Michelle
    Gallardo, 2 Locks Opened During Record Rainfall, Chicago
    Tribune, July 25, 2011, http://abclocal.go.com/wls/story?
    section=news/ local&id=8270514. It also happened exactly
    one year before, on July 24, 2010.) A related complication
    concerns how effectively the locks stop fish even when they
    are closed. By most accounts, a watertight closure would
    require bulkheads to be installed on the locks. Without
    bulkheads, fish might slip through small openings. The
    states have been less than explicit about whether their ideal
    injunction would require bulkheads, but if it would, then all
    the risks of flooding come right back into the equation.
    Bulkheads take time to install and remove, which means
    that it would be very difficult to respond quickly to floods.
    In short, this aspect of the states’ requested relief puts them
    into a bind: the risk of carp migration is reduced the most by
    closing the locks permanently with bulkheads; but that
    measure, as the states recognize, would dramatically
    escalate the costs imposed by flooding. While keeping the
    locks closed more often no doubt reduces the risk of fish
    migrating into Lake Michigan, it does not bring it down to
    zero. And this unquantified reduction in risk comes with an
    increased immediate burden on public health and safety
    measures.
    44                                                 No. 10-3891
    b. Screens over Sluice Gates. The states encounter similar
    problems with their request that the defendants screen off
    nine additional sluice gates. The District operates these huge
    gates, which open and close to adjust the rate of water flow,
    as part of its diversion effort – the process of drawing water
    out of Lake Michigan and into the CAWS to maintain
    navigability and water quality. In addition, when heavy
    rains occur, sluice gates (like the locks) are opened to let
    water from the CAWS into the lake. There are eight sluice
    gates at the Controlling Works, four at O’Brien, and one in
    Wilmette. To prevent the migration of adult carp, the
    District already has installed four screens over sluice gates:
    two at the Controlling Works and two at O’Brien. The
    District uses the four screened-off gates for diversion; the
    other nine remain closed except during flooding.
    Initially, the states wanted to force the defendants to close
    all of the gates, except when public health or safety might be
    harmed. They have revised that request so that now they ask
    for screens over the nine remaining sluice gates at these
    sites. This request would mitigate the risk of carp migration
    only (at best) during floods, for at other times the gates,
    unlike the locks, are closed anyway. Further reducing the
    effectiveness of this measure is the fact that in some flooding
    incidents where additional sluice gates must be opened, the
    locks must be opened as well. Screens over additional sluice
    gates would not do much good if fish could swim through
    open locks. Finally, all available evidence suggests that it
    will take a long time for the District to acquire additional
    property, to research feasible options for a system of screens
    that will not become clogged with debris during flooding,
    and to build those screens. This means that this portion of
    the states’ preliminary injunction might not even be in place
    before the full trial on the merits has concluded. For all of
    these reasons, we think that installing screens over sluice
    gates will have at most a tiny effect on the odds of invasive
    carp making it to Lake Michigan.
    c. Block Nets in the Rivers. The prospect of placing block
    nets in the Little Calumet and Grand Calumet Rivers strikes
    No. 10-3891                                                                     45
    us as potentially the most effective element of the proposed
    relief. At the time of oral argument, the states asked that the
    Corps place block nets only in the Little Calumet River; at
    that point, a cofferdam in the Grand Calumet River
    prevented fish migration and alleviated the need for nets
    there. We will assume that were this dam removed, the
    states would ask the Corps to place nets in the Grand
    Calumet River as well. The Corps, however, has said that it
    is already looking at the possibility of installing nets in both
    waterways, but that it is concerned that flooding will
    increase as debris becomes caught in the nets. The states
    respond that block nets could be cut free and replaced with
    new nets if risks of flooding materialized. All of the parties
    are vague about the possibilities and implications of this
    plan. At this stage, it is enough to say that this step seems
    more promising than others when it comes to mitigating the
    risk that fish will appear in Lake Michigan. We take the
    Corps at its word that this option is under serious
    consideration and would be implemented if and when a
    feasible plan can be developed.
    d. Rotenone Poisoning. In contrast to the block net idea, the
    suggestion that the Corps use rotenone to poison fish in the
    CAWS seems untenable to us. Rotenone is a chemical that
    acts as a piscicide when it is released in a body of water.
    Though humans would not digest much of it if it were
    ingested, rotenone enters the bloodstream of a fish through
    the gills, causing death quickly. Rotenone dumped into a
    river kills the vast majority of fish living there; when dead,
    they usually float to the surface. The poison generally is less
    dangerous to other animals, but it is toxic and its toxicity
    varies depending on the species. See generally Cornell
    University, Resource Guide for Organic Insect and Disease
    Management, Material Fact Sheets - Rotenone,
    h tt p ://w e b .p p p m b .c a l s .c o r n e l l .e d u / r e s o u r c e gu id e/
    mfs/11rotenone.php. It is unclear just how the states’
    proposal for rotenone use differs from what the Corps is
    already doing in the CAWS. We know that the states would
    like poison to be applied near O’Brien, but there is no
    46                                                No. 10-3891
    indication how often or where else it might be used. In May
    2010, the Corps and other agencies used the poison to search
    for fish in a two-mile stretch of the Little Calumet River.
    Dozens of tons of fish were killed, and no specimens of
    invasive carp were found. While poisoning may be an
    effective way to search for elusive carp in some
    circumstances, the record does not explain why ordering the
    Corps to poison the CAWS on a regular basis would be a
    sound step toward reducing the risk that invasive carp will
    migrate into the Great Lakes.
    e. Accelerating GLMRIS. That brings us to the aspect of the
    proposed injunction that would require the Corps to
    accelerate its long-term study of ways in which it might
    permanently prevent the migration of invasive species
    (including, but not limited to, the carp) between the Great
    Lakes and the Mississippi basins. The states raise a side
    issue here, saying that the district court erred when it denied
    their request to expedite GLMRIS because it failed to make
    the findings required by Federal Rule of Civil Procedure
    52(a)(2). The argument is frivolous. The district court
    explained its reasons for denying all of the relief that the
    states sought. The court had – and will continue to have as
    the case moves forward – the power to grant or deny
    equitable measures either in whole or in part. It did not need
    to discuss every facet of the relief requested.
    According to the Corps, GLMRIS examines every potential
    pathway between the two watersheds and proposes
    solutions to stop migration through each one. Examination
    of the CAWS, which the Corps intends to finish by 2015, is
    just one portion of the study. The Corps adds that it has the
    power to implement solutions that are devised as the study
    progresses. The states would like the court to order the
    Corps to finish the CAWS portion of GLMRIS within 18
    months. They are not the only ones who have criticized the
    study for taking too long; the City of Chicago and others
    have as well. See, e.g., Dan Egan, Chicago Urges Army Corps
    to Report on Carp Sooner, Milwaukee Journal Sentinel, Apr.
    10,     2011,       http://www.jsonline.com/
    No. 10-3891                                                 47
    news/wisconsin/119547049.html. It may well be that faster
    action is appropriate if possible; and, as the Corps conceded
    during oral argument, it may be necessary for the Corps to
    implement measures devised through GLMRIS on a rolling
    basis. But we do not see how a preliminary injunction that
    would essentially ask the Corps to study harder and think
    faster would reduce the odds that invasive carp will
    establish themselves in the short term.
    When we take all five aspects of the states’ proposed
    injunction together, we can say only that there is some
    evidence that the relief sought would reduce by an
    undefined amount the risk of carp establishing a breeding
    population in the Great Lakes. It is equally apparent,
    however, that the steps the states have proposed offer no
    assurance that they will block the carp over the short run or,
    over the long run, that they will save the Great Lakes
    ecosystem and the $7 billion industry that depends on that
    ecosystem. We must therefore turn to the other side of the
    equation: the harm that the proposed steps would inflict on
    the opponents of preliminary relief.
    3
    The states have adopted a rather insouciant attitude about
    the potential harm that their proposal might inflict. “[T]he
    federal government has made it clear that it is willing to
    spend significant resources to reduce this threat,” the states
    write, “so the cost of a few bulkheads should not prove a
    serious impediment to protecting the Great Lakes.” This
    tone continues throughout their briefs, with remarks like,
    “While the Corps asserts that the Coast Guard doesn’t have
    the funds to [dock additional ships on both sides of locks
    that would be closed by the injunction], this is just a matter
    of money.” Of course this dispute is in part a matter of
    money; but scoffing at the defendants’ concerns about the
    costs of relief does not aid our assessment of the expense of
    the relief that the states want. It should go without saying in
    these straitened times that the federal and local governments
    do not have bottomless coffers. Indeed, 19 members of the
    48                                                  No. 10-3891
    plaintiff states’ delegations to Congress recently voted
    against raising the federal borrowing limit. Nor do we
    understand why the states take this view when they
    apparently feel no obligation to contribute to the costs of
    averting this crisis. When we inquired at oral argument how
    the costs of the proposed injunction should be apportioned
    among the parties, the states informed us that their citizens
    would contribute to the costs by paying federal income
    taxes. This is not very helpful. Indeed, one might wonder
    why the federal government and the State of Illinois should
    be saddled with the entire cost of an injunction that is aimed
    at a problem that has been developing for four decades in a
    watershed that touches roughly half of the states in the
    Union.
    To make matters worse, both sides throw around large
    numbers to make the case that the balance of harms favors
    their position. We have already explained why the proposed
    injunction is quite unlikely to prevent the states’ forecasted
    $7 billion in harm. But the defendants invent similarly
    extreme costs. We are told repeatedly that almost $2 billion
    in cargo moves through locks in the CAWS each year. This,
    however, is not the cost that an injunction would impose on
    commercial shipping. If the locks were closed, cargo would
    have to be loaded from ships onto ground transportation at
    some point along the journey. Estimates of the cost of
    off-loading range from about $70 million per year (from the
    plaintiffs’ perspective) to $150 million (according to the
    Corps). The intervening defendant Coalition to Save Our
    Waterways, which represents various business interests,
    tells us that closing the locks would cost $4.7 billion. We find
    no support in the record for that astronomical estimate. The
    dollar value of the harm to either side is of course difficult to
    calculate, but we need not settle on a precise number to
    resolve this appeal.
    If the requested preliminary injunction were to issue, we
    can be sure that it would impose significant costs. First, we
    would have the expenses of implementing all of the
    measures that the states have recommended. In addition,
    No. 10-3891                                                 49
    funds that the defendants spend complying with the
    injunction likely would be diverted from other agency
    efforts to curb invasive carp. If we required the Corps to
    complete its long-term study within 18 months, the Corps
    suggests that it would not have time study the problem
    comprehensively and that the study might not adequately
    support any proposed solutions. The prospect of closing the
    locks permanently, installing screens on sluice gates, and
    placing block nets in the CAWS increases the risk of
    flooding, which (to the extent that it occurs) would impose
    costs throughout the region. The states say that there are
    ways to avoid those costs. The locks, for example, could be
    opened at the District’s discretion during flooding. But, as
    we have explained, this would be possible only if the states
    agreed that bulkheads were not necessary. (The states argue
    that bulkheads could be removed by a barge and crane to
    permit for flood relief. Even if that were possible, stationing
    barges at both locks would cost thousands of dollars per
    day.) Screens installed over sluice gates used during
    flooding could become clogged, and the states’ suggestion
    that raking systems be installed to alleviate this concern is
    both untested and would required significant additional
    expenditures. Meanwhile, closing the locks to boat traffic
    would have a tremendous impact. Police and fire services on
    which the City of Chicago relies would not be able to move
    from the Chicago River and other points in the CAWS to
    Lake Michigan, which means that the city would have to
    establish redundant emergency response fleets on either side
    of the locks. The same goes for Coast Guard operations
    around the CAWS. Recreational and tourist vessels would
    be stopped. And last but certainly not least, closed locks
    would mean that all commercial shipping in the area
    between the Great Lakes and the Mississippi would have to
    find alternative routes.
    We can stop there. This overview demonstrates that the
    preliminary injunction the states have requested would
    impose substantial costs, yet given the current state of the
    record, we are not convinced that the preliminary injunction
    50                                                 No. 10-3891
    would assure much of a reduction in the risk of the invasive
    carp establishing themselves in Lake Michigan in the near
    future. That the balance of harms at this stage of the
    litigation favors the defendants might be enough by itself to
    support a conclusion that preliminary relief is not
    warranted, even though we have concluded that the states
    have demonstrated a likelihood of success on the merits and
    a threat of irreparable harm. See Hoosier Energy Rural Elec.
    Co-op v. John Hancock Life Ins. Co., 
    582 F.3d 721
    , 725 (7th Cir.
    2009) (describing the relation between the harm prevented
    by the plaintiff’s proposed injunction and the strength of a
    plaintiff’s claim for preliminary relief). Even if one were to
    conclude that the harms are in equipoise, however, there is
    a final reason why preliminary injunctive relief is not
    warranted. As things now stand, the case for judicial
    intervention is refuted by the fact that the competent federal
    and state actors are actively pursuing an array of efforts to
    solve the problem of invasive carp.
    B
    1
    While American Electric Power is a case about congressional
    displacement of federal common law, the Supreme Court
    took the opportunity to touch generally on the relative
    competence of courts and expert agencies when it comes to
    solving complex environmental problems. “It is altogether
    fitting that Congress designated an expert agency, here,
    EPA, as best suited to serve as primary regulator of
    greenhouse gas emissions,” the Court wrote, explaining
    further:
    The expert agency is surely better equipped to do the job
    than individual district judges issuing ad hoc,
    case-by-case injunctions. Federal judges lack the
    scientific, economic, and technological resources an
    agency can utilize in coping with issues of this order.
    Judges may not commission scientific studies or
    convene groups of experts for advice, or issue rules
    under notice-and-comment procedures inviting input by
    No. 10-3891                                                    51
    any interested person, or seek the counsel of regulators
    in the States where the defendants are located. Rather,
    judges are confined by a record comprising the evidence
    the parties present. Moreover, federal district judges,
    sitting as sole adjudicators, lack authority to render
    precedential decisions binding other judges, even
    members of the same court.
    American Electric Power, 
    131 S. Ct. 2539
    -40 (internal citation
    omitted). This limitation of the judiciary is a familiar feature
    of American law. See, e.g., Negusie v. Holder, 
    129 S. Ct. 1159
    ,
    1171 (2009) (Stevens, J., concurring in part and dissenting in
    part); Kelo v. City of New London, 
    545 U.S. 469
    , 487-88 (2005);
    Lingle v. Chevron U.S.A., Inc., 
    544 U.S. 528
    , 544-45 (2005);
    Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 
    467 U.S. 837
    , 865-66 (1984); Tennessee Valley Authority v. Hill, 
    437 U.S. 153
    , 194-95 (1978).
    Our sister circuits have explored the impact of this
    inherent limitation of the judicial role in cases comparable to
    ours. The Second Circuit has written that “[c]ourts
    traditionally have been reluctant to enjoin as a public
    nuisance activities which have been considered and
    specifically authorized by the government.” New England
    Legal Found. v. Costle, 
    666 F.2d 30
    , 33 (2d Cir. 1981). In the
    same vein, the Fourth Circuit recently reversed a lower
    court’s decision to enter an injunction that would have
    required the TVA to implement new emissions controls.
    North Carolina, ex rel. Cooper, 
    615 F.3d 291
    . The district court
    in that case entered an injunction after North Carolina sued
    the TVA for air pollution based on a state common-law
    public nuisance theory. The court of appeals concluded that
    granting “the injunction would encourage courts to use
    vague public nuisance standards to scuttle the nation’s
    carefully created system for accommodating the need for
    energy production and the need for clear air.” 
    Id. at 296
    .
    Though the case involved a more robust regulatory scheme
    than the one that has been cobbled together for the invasive
    carp, the court’s discussion is instructive insofar as it relates
    to the problems created when courts attempt to stop a
    52                                                  No. 10-3891
    nuisance at the same time that agencies are working to solve
    the problem. An approach that would allow the federal
    court and the EPA simultaneously to regulate a single
    emissions problem, said the Fourth Circuit, would result in
    multiple and perhaps contradictory decrees emanating from
    different branches of government and confusion about what
    standards should govern air pollution. 
    Id. at 301-04
    . In
    addition, judicial action in the face of strong agency
    measures “would reorder the respective functions of courts
    and agencies.” 
    Id. at 304
    . Environmental problems require
    the balancing of many complicated interests, and agencies
    are better suited to weigh competing proposals and select
    among solutions. 
    Id. at 305
     (“[W]e doubt seriously that . . . a
    judge holding a twelve-day bench trial could evaluate more
    than a mere fraction of the information that regulatory
    bodies can consider.”).
    None of this means that courts can no longer craft
    remedies designed to abate a public nuisance. In light of the
    general approach the Supreme Court took in American
    Electric Power, however, it does mean that the court should
    not blind itself to other remedies that are available under the
    law or to other measures that are actively being pursued to
    solve the problem. Even if legal displacement like that found
    in American Electric Power does not exist, the practical effect
    of agency actions might add up to displace as a matter of
    fact any role that equity might otherwise play. Efforts of
    other branches of government might be so complete that
    additional action ordered by a court would risk
    undermining agency efforts to abate the nuisance. How
    much the equitable power of the court has been limited by
    agency action will be a factual question that turns on the
    quality and quantity of the agency’s (or, as here, agencies’)
    efforts. This kind of institutional consideration of the court’s
    relative ability to craft meaningful relief fits naturally in the
    balance-of-harms analysis. For if an injunction might
    hamper agency efforts or can improve upon them only
    slightly, that is all the more reason to conclude that the
    equities tilt in favor of the defendant.
    No. 10-3891                                                     53
    2
    The record in this case leaves no doubt that federal and
    state agencies, executive officials, and working groups have
    mounted a tremendous effort to halt the migration of
    invasive carp. As we have already mentioned, the Aquatic
    Nuisance Prevention and Control Act of 1990 created the
    Aquatic Nuisance Species Task Force, which includes among
    other agencies the National Oceanic and Atmospheric
    Administration, the U.S. Fish and Wildlife Service, the U.S.
    Geological Survey, and the EPA. This task force coordinates
    invasive species issues generally across the country. In
    addition, during the fall of 2009, 21 federal, state, and local
    agencies and other entities combined forces to form the
    Asian Carp Regional Coordinating Committee (the ACRCC),
    which is designed (as the name suggests) to track and to
    stop the migration of invasive carp. See generally Asian
    Carp Control, http://www.asiancarp.org/. The ACRCC
    counts as members those agencies that comprise the task
    force, the Corps and the District, the Coast Guard, the U.S.
    Department of Transportation, the White House Council on
    Environmental Quality, the Great Lakes Fishery
    Commission, the City of Chicago, and the state departments
    of natural resources of all of the plaintiff states, plus Illinois,
    Indiana, and New York.
    In order to stop the invasive carp, the ACRCC has
    developed what it calls the “Asian Carp Control Strategy
    Framework,” which is now in its third edition. The most
    recent document lists over 40 collaborative projects that the
    working group has designed to deal with invasive carp;
    many of these initiatives are underway or have been
    completed already. As the ACRCC describes it, the projects
    fall into eight categories:
    (1) targeted monitoring assessment activities above and
    below the electric barrier system, including enhanced
    monitoring above and below the barriers, electrofishing,
    and rapid response teams;
    (2) commercial harvesting and removal actions below
    54                                                No. 10-3891
    the electric barriers (which involves fishing and removal
    of fish in the Lockport area, where the CAWS connects
    to the Des Plaines River; creating new markets for the
    fish; and investigating certification requirements for
    invasive carp to be sold commercially);
    (3) electric barrier actions and waterway separation
    measures (consisting of the construction of barriers
    between various waterways so that fish cannot move
    from one to the other during flooding; expedited
    construction of the now-completed third electric barrier;
    fish tagging to test the effectiveness of the barriers; and
    separation of various watersheds that pose risks);
    (4) myriad studies on how best to separate the
    watersheds; the effectiveness of various measures; and
    risk modeling;
    (5) research and technology development (including
    investigation of how fish move around the CAWS; food
    sources for invasive carp in the lakes and how those
    sources might be eliminated; the use of seismic
    technology to divert or kill invasive carp; attraction and
    repulsion pheromones of invasive carp; creation of toxin
    screens to kill fish; study of the weaknesses of carp to
    different toxins; physical barriers; reducing carp egg
    viability; and new detection methods, among other
    things);
    (6) eDNA analysis and refinement (which involves
    monitoring and sampling for eDNA in the CAWS and
    increasing the effectiveness of eDNA testing);
    (7) enforcement activities designed to prevent people
    from transferring carp between bodies of water; and
    (8) work on funding, including the development of
    methods to pay for measures among the contributing
    groups.
    In addition, the ACRCC has established three working
    groups: monitoring and rapid response; invasion control;
    No. 10-3891                                                   55
    and communication and outreach.
    What we have described already reflects a substantial
    effort, but there is more. The Corps has been fulfilling the
    marching orders that it has received from Congress. In
    addition to the electric barriers and GLMRIS, which we have
    discussed in detail, we have mentioned the Corps’s study of
    the effectiveness of its three electric barriers for stopping the
    movement of invasive carp through the CAWS. The final
    version of the Efficacy Study is due later this year, but there
    already have been four interim reports (numbered in typical
    bureaucratic fashion as Interim I, II, III, and IIIA), and the
    Corps has implemented measures pursuant to some of these
    reports. Interim I identified an area where the Des Plaines
    River and the Chicago Sanitary and Ship Canal are so close
    together that carp could wash between them during floods.
    (The plaintiffs had argued in their complaint that this area
    represented a huge problem.) The Corps has since built a
    fence to stop migration between these waterways, and that
    fence has already proven effective. Meanwhile, Interim II,
    which is not yet completed, will set operational parameters
    for the three electric barriers so that they can most effectively
    deter the movement of invasive species. The Corps says that
    even though this study is not finished, it now operates the
    barriers at the maximum safe strength. In connection with its
    Interim III report, the Corps consulted a panel of experts
    about a number of potential changes to its operation of the
    CAWS. The report concluded that additional screens should
    be installed on sluice gates, and the District responded by
    adding screens to two gates at O’Brien, which supplemented
    the two it had installed months earlier at the Controlling
    Works. In addition, Interim III recommended that the
    District cease using the sluice gate at Wilmette for diversion,
    and it hypothesized that the District might be able to create
    “atoxic zones” in the CAWS that would be so toxic that no
    fish would ever be able to swim through them. Finally, the
    Corps in Interim IIIA recommended the construction of an
    acoustic, air-bubble, and strobe-light curtain (more or less a
    disco screen), which would be designed to frighten fish back
    56                                                No. 10-3891
    toward the Mississippi. The disco screen has not been
    started, but the Corps represented to us at oral argument
    that it intends to undertake the project at some location
    downstream of the existing electric barriers.
    In addition to the measures outlined in the interim efficacy
    reports, the agencies continue to rely on traditional methods
    to monitor and kill invasive carp, including tracking,
    netting, electrofishing, and rotenone poisoning; and, as we
    have discussed, they have also continued eDNA testing
    throughout the CAWS. Where eDNA reveals a potential
    threat, the agencies have responded with days-long hunts
    for invasive carp. Continual fishing south of the CAWS
    reduces the propagule pressure that would otherwise push
    carp closer to Lake Michigan. Finally, the Obama
    Administration has named an “Asian carp czar,” who is
    charged with leading the administration’s effort to stop
    invasive carp. Recently, the administration announced plans
    to install a high-intensity water cannon that would deter fish
    by firing huge, underwater blasts of water across Chicago
    Ship and Sanity Canal.
    It is our understanding that the defendants and the
    agencies we have just discussed are actively pursuing the
    measures that we have just described. In addition, where the
    defendants have represented that future steps will be taken
    – whether a disco screen, the water gun, operating the
    electric barriers at optimal settings, considering the
    possibility of block nets in the CAWS, completing and
    implementing GLMRIS in phases, continuing to monitor
    aggressively with traditional and eDNA techniques, or any
    of the other actions we have highlighted – we have no
    reason at this point to assume that this work will not be
    done. Whatever happens, the plaintiff states will continue to
    have a seat at the table as these and future plans are made
    and implemented. We conclude that on this record, there is
    nothing that any preliminary injunction from the court could
    add that would protect the Great Lakes from invasive carp
    while this suit is being adjudicated any better than the
    elaborate measures we have just described. This tips the
    No. 10-3891                                                57
    balance of harms decisively in favor of the defendants.
    VI
    We take very seriously the threat posed by the invasive
    species of carp that have come to dominate parts of the
    Mississippi River basin and now stand at the border of one
    of the most precious freshwater ecosystems in the world.
    Any threat to the irreplaceable natural resources on which
    we all depend demands the most diligent attention of
    government. As the case proceeds, the district judge should
    bear in mind that the risk of harm here depends upon both
    the probability of the harm and the magnitude of the
    problem that would result. In the end, however, the question
    whether the federal courts can offer meaningful equitable
    relief – either preliminary or permanent – to help abate a
    public nuisance in the face of agency action is factual in
    nature . It depends on the actual measures that the agencies
    have implemented already and those that they have
    committed to put in place going forward. Our ruling today
    is tied to our understanding of the current state of play. We
    recognize that the facts on the ground (or in the water) could
    change. The agencies currently working hard to solve the
    carp problem might find themselves unable to continue, for
    budgetary reasons, because of policy changes in
    Washington, D.C., or for some other reason. If that happens,
    it is possible that the balance of equities would shift.
    Similarly, new evidence might come to light which would
    require more drastic action, up to and including closing
    locks on Lake Michigan for a period of time. If either
    situation comes to pass, then the district court would have
    the authority to revisit the question whether an exercise of
    its equitable powers is warranted, taking into account the
    principles we have discussed in this opinion. As things
    stand now, however, preliminary relief is not appropriate.
    The district court’s judgment is AFFIRMED.
    

Document Info

Docket Number: 10-3891

Judges: Wood

Filed Date: 8/24/2011

Precedential Status: Precedential

Modified Date: 9/24/2015

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