Nos. 14-­--1776 & 14-­--1777 UNITED STATES OF AMERICA and STATE OF ILLINOIS v. Metropolitan Water Reclamation District of Greater Chicago

In the
United States Court of Appeals
For the Seventh Circuit
____________________
Nos. 14-­‐‑1776 & 14-­‐‑1777
UNITED STATES OF AMERICA and STATE OF ILLINOIS,
Plaintiffs-­‐‑Appellees,
and
ALLIANCE FOR THE GREAT LAKES, et al.,
Intervening Plaintiffs-­‐‑Appellants,
v.
METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER
CHICAGO,
Defendant-­‐‑Appellee.
____________________
Appeals from the United States District Court for the
Northern District of Illinois, Eastern Division.
No. 11 C 8859 — George M. Marovich, Judge.
____________________
ARGUED FEBRUARY 12, 2015 — DECIDED JULY 9, 2015
____________________
Before EASTERBROOK, KANNE, and HAMILTON, Circuit
Judges.
EASTERBROOK, Circuit Judge. So much of the Chicago met-­‐‑
ropolitan area is covered with concrete or other impermea-­‐‑
ble surfaces that the remaining ground cannot absorb the

-- 1 of 13 --

2 Nos. 14-­‐‑1776 & 14-­‐‑1777
water from heavy rain. The excess goes into a combined
stormwater and sewer system, which can overflow and es-­‐‑
cape through outfalls located on the banks of canals and riv-­‐‑
ers. In 1975 the Metropolitan Water Reclamation District,
which manages sewage control (including purification
plants), began construction on an ambitious project to im-­‐‑
pound water until it can be cleaned up and released safely:
the Tunnel and Reservoir Plan, sometimes called TARP and
commonly known as Deep Tunnel.
About 110 miles of large-­‐‑diameter tunnels, as much as
350 feet underground (hence “deep” tunnel), collect runoff
water and sewage during rainfall. But these tunnels, large
and extensive as they are, can hold “only” 2.3 billion gallons
of water, and heavy or extended rain may exceed that capac-­‐‑
ity. The plan therefore includes reservoirs, to which the tun-­‐‑
nels direct their contents during high-­‐‑inflow conditions. Two
reservoirs, which between them can hold 3.4 billion gallons,
are operational today. One of these is scheduled to be re-­‐‑
placed later this year by the Thornton Composite Reservoir,
which can accommodate 4.8 billion gallons from TARP.
(This reservoir can hold 7.9 billion gallons, but 3.1 billion
gallons of that capacity is for overflow from Thorn Creek
and is not counted as part of the Deep Tunnel system.) The
final piece of the system, the McCook Reservoir, is sched-­‐‑
uled for completion in 2029 with a capacity of 10 billion gal-­‐‑
lons (and an interim capacity of 3.5 billion gallons by 2017).
Deep Tunnel’s final capacity will be 17.5 billion gallons.
The Thornton and McCook reservoirs have taken a long
time to build because both will occupy worked-­‐‑out lime-­‐‑
stone quarries. The demand for limestone, which has de-­‐‑
clined in recent years, affects the date of completion. (Paying

-- 2 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 3
to have limestone dug up in advance of demand from build-­‐‑
ing and roadwork projects not only would be expensive but
also would require the acquisition of land on which to dump
huge piles of limestone, which would be unsightly and also
create environmental problems as minerals leached from the
limestone during rain.) But the delay in finishing the reser-­‐‑
voirs, plus some problems in the design of the tunnels that
can require the District to hold them below capacity, have
hindered the system’s ability to prevent stormwater and
sewage releases. The record does not show how many un-­‐‑
treated releases occur annually at the approximately 375 lo-­‐‑
cations along rivers and canals where this is possible. It does
show that flows from all sources (including direct rain run-­‐‑
off) are so substantial approximately once a year that the
rivers and canals themselves would overflow unless permit-­‐‑
ted to discharge into Lake Michigan (normally locks prevent
this, but they are opened when necessary to keep the rivers’
levels under control).
In 2011 the United States and the State of Illinois jointly
filed this suit, under sections 301 and 309 of the Clean Water
Act, 33 U.S.C. §§ 1311, 1319, seeking an order that the Dis-­‐‑
trict improve the TARP’s performance, accelerate its comple-­‐‑
tion date, and do more to contain and mitigate overflows in
the interim. The district court permitted the Alliance for the
Great Lakes and four other environmental organizations
(collectively the Alliance) to intervene under 33 U.S.C.
§1365(b)(1)(B). See 2012 U.S. Dist. LEXIS 111223 (N.D. Ill.
Aug. 7, 2012).
The complaint was accompanied by a proposed consent
decree, which the pollution-­‐‑control agencies had been nego-­‐‑
tiating with the District for four years. The settlement re-­‐‑

-- 3 of 13 --

4 Nos. 14-­‐‑1776 & 14-­‐‑1777
quires the District to complete the Deep Tunnel project, meet
operational criteria when construction has been completed,
monitor the system’s performance, develop additional
measures if needed to attain compliance with the Act and
applicable permits in the interim, and maintain the decree in
force until the district court concludes that compliance with
the Act has been achieved. The Alliance opposed this pro-­‐‑
posal, contending that it requires the District to do too little
and takes too long even for what it accomplishes. In a
lengthy opinion, the district court rejected the Alliance’s pro-­‐‑
test and entered the proposed decree. 2014 U.S. Dist. LEXIS
2049 (N.D. Ill. Jan. 6, 2014). The opinion contains many de-­‐‑
tails about the settlement that we do not need to recapitu-­‐‑
late, though we describe a few details later.
The district judge also concluded that the settlement
binds the Alliance, and we start with this decision. A consent
decree is at base a contract, see United States v. ITT Continen-­‐‑
tal Baking Co., 420 U.S. 223 (1975), and the Alliance asks how
it can be bound by a contract to which it did not agree. The
district court’s answer was “res judicata” (the combination
of issue and claim preclusion), but that doctrine prevents one
party from litigating the same claim or issue in multiple suits.
See Robinson v. Harvey, 617 F.3d 915, 916 (7th Cir. 2010). The
Alliance is not the United States or the State of Illinois, and
there is only one lawsuit. The district court relied on Friends
of Milwaukee’s Rivers v. Milwaukee Metropolitan Sewerage Dis-­‐‑
trict, 382 F.3d 743, 757–65 (7th Cir. 2004), and United States v.
Metropolitan St. Louis Sewer District, 952 F.2d 1040 (8th Cir.
1992), but each of these decisions dealt with multiple suits
(filed only a few hours apart in Friends of Milwaukee’s Rivers).

-- 4 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 5
Our situation is governed not by principles of res judicata
but by the fact that legislation may allocate litigation rights
to an agency that represents the whole public. See Taylor v.
Sturgell, 553 U.S. 880, 895 (2008) (discussing the sixth excep-­‐‑
tion to the norm that principles of virtual representation do
not generally bind one person to the results of another’s
suit); Restatement (Second) of Judgments §41(1)(d). The statute
modifying the common law is §1365(b), which provides:
No action may be commenced—
(1) under subsection (a)(1) of this section [which authorizes
private suits to enforce the Clean Water Act]—
(A) prior to sixty days after the plaintiff has given no-­‐‑
tice of the alleged violation (i) to the Administrator [of
the EPA], (ii) to the State in which the alleged violation
occurs, and (iii) to any alleged violator of the standard,
limitation, or order, or
(B) if the Administrator or State has commenced and is
diligently prosecuting a civil or criminal action in a
court of the United States, or a State to require compli-­‐‑
ance with the standard, limitation, or order, but in any
such action in a court of the United States any citizen
may intervene as a matter of right.
Section 1365(b)(1)(B) tells us that no private litigation may be
“commenced” if the EPA or a state “has commenced and is
diligently prosecuting a civil … action” about the same mat-­‐‑
ter the private litigant wants to raise.
We held in Friends of Milwaukee’s Rivers that this language
also means that the resolution (including a settlement) of a
federal or state suit is binding on a private litigant whose
suit was filed after the state or federal government’s, if the
state or federal action was diligently prosecuted. Accord,
Louisiana Environmental Action Network v. Baton Rouge, 677

-- 5 of 13 --

6 Nos. 14-­‐‑1776 & 14-­‐‑1777
F.3d 737, 749–50 (5th Cir. 2012); Piney Run Preservation Asso-­‐‑
ciation v. Carroll County, 523 F.3d 453, 459–60 (4th Cir. 2008).
The United States and Illinois contend that the outcome of a
governmental suit is equally conclusive for private claims
asserted by intervenors.
This leads the Alliance to ask what the point of interven-­‐‑
tion might be—for intervention, no less than a ban on stand-­‐‑
alone private litigation, is part of this scheme. The answer,
we think, is that intervention carries four rights: to introduce
evidence if the case goes to trial; to object to a proposed set-­‐‑
tlement (a right the Alliance has exercised); to appeal if the
intervenor thinks that the government has accomplished too
little (another right the Alliance has exercised); and to en-­‐‑
force any judgment, just as the United States and Illinois can
do. This decree orders the District to come into compliance
with the Act and its permits, providing details about how
and when. If the District falls short, either in implementing
the interim measures or achieving compliance by 2029, then
the Alliance can ask the district court for relief. And if the
District asks the district court to dissolve the decree in 2030,
the Alliance, as a party, can protest that too and appeal from
an adverse decision.
That is a more modest role than a full-­‐‑fledged independ-­‐‑
ent litigator would have, but §1365(b)(1)(B) tells us that a
private party is not supposed to be a full-­‐‑fledged independ-­‐‑
ent litigator, if the state or federal government diligently
prosecutes a suit. This is also the implication of the Supreme
Court’s observation that private intervenors are supposed to
“supplement rather than to supplant” public litigation.
Gwaltney of Smithfield, Ltd. v. Chesapeake Bay Foundation, Inc.,
484 U.S. 49, 60 (1987). If the Alliance could carry on just as if

-- 6 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 7
it were the plaintiff in a separate suit, that would “supplant”
the governmental case. Why would anyone settle with the
EPA or a state, if the settlement did not buy peace? The Dis-­‐‑
trict made costly promises, but if the Alliance is right then it
got nothing in return, for the Alliance can carry on with the
suit. And if the Alliance also settled, then another person
could intervene to demand still more relief. Depriving the
original parties of their ability to settle disputes is not con-­‐‑
sistent with the observation in Gwaltney, the holding of
Friends of Milwaukee’s Rivers, or the structure of §1365(b).
Section 1365(b)(1)(B) blocks stand-­‐‑alone private litigation
only if the public agencies “diligently” prosecute their suits.
The Alliance maintains that if there is a chance that the con-­‐‑
sent decree will fail to achieve full compliance with the Act
and all permits, then the government has not prosecuted the
claims diligently. That can’t be right. Even the most diligent
litigator may conclude that settlement is the best option—if
only because it frees up enforcement resources for use else-­‐‑
where—and to achieve a settlement a litigant must accept
something less than the most favorable outcome.
In Friends of Milwaukee’s Rivers we concluded that a set-­‐‑
tlement likely to achieve the principal enforcement goals
demonstrates diligent prosecution. 382 F.3d at 759–60. For a
settled case, this pretty much turns the diligence issue into
the question whether the proposed consent decree is reason-­‐‑
able. We remanded in Friends of Milwaukee’s Rivers because
the district court had approved that settlement without in-­‐‑
quiring how likely it was to be an adequate solution. Here,
by contrast, the district court considered the proposal’s ade-­‐‑
quacy at length and evaluated the Alliance’s objections. This
enables us to merge the inquiries: if the consent decree is a

-- 7 of 13 --

8 Nos. 14-­‐‑1776 & 14-­‐‑1777
reasonable settlement likely to bring about compliance with
the Act, it also demonstrates diligent prosecution.
The Clean Water Act forbids “the discharge of any pollu-­‐‑
tant” (a defined phrase, see South Florida Water Management
District v. Miccosukee Tribe, 541 U.S. 95 (2004)), except when
authorized by permits. The District holds multiple permits
that govern releases from its system. These permits recog-­‐‑
nize the inevitability of discharges during storms but impose
three kinds of conditions: the discharged water must have
minimum oxygen levels, must keep solid matter (“floata-­‐‑
bles”) under a specified level, and must provide for some
rudimentary treatment (what the permits call “primary
treatment … with adequate retention time”).
The federal and state complaint alleges that some over-­‐‑
flows do not meet one or more of these three conditions. If
the Deep Tunnel plan, augmented by the provisions of the
consent decree, succeeds, then by 2029 (if not earlier) it will
be possible to retain the water long enough to route it
through the District’s seven treatment plants at a rate that
will allow full treatment. But the Alliance predicts that it will
not succeed. The district court rejected the Alliance’s protests
in part because the alternatives it proposed would be costly
(more than $1 billion), much of which would turn out to be
wasted if the state and federal government are right about
the plan’s adequacy, and because even if the Alliance’s pre-­‐‑
dictions are right the rate of backflows from rivers and ca-­‐‑
nals into Lake Michigan will drop from once a year to once a
decade when the system is finished.
The Alliance’s main argument on appeal can be summed
up as: “It just won’t work.” The argument has three compo-­‐‑
nents. First, a study completed in 1994, and the testimony of

-- 8 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 9
one of the District’s consultants before the Illinois Pollution
Control Board, state that heavy rainfall will overwhelm the
Deep Tunnel system. But the EPA, the Pollution Control
Board, and the District are more optimistic about the sys-­‐‑
tem’s likely functioning when completed. Dissatisfied with
the 1994 study, which was based on only one modeled rain-­‐‑
fall event and did not analyze the system’s current opera-­‐‑
tional plan, the EPA conducted its own. This new study, re-­‐‑
leased in 2009, concluded that the finished Deep Tunnel sys-­‐‑
tem will work, at least during average and above-­‐‑average
rainfall years. (The study did not consider once-­‐‑in-­‐‑100-­‐‑year
events and other huge storms.) Recent data covering 2005
through 2011 in the Upper Des Plaines segment of the TARP
system, which is finished (including its full reservoir capaci-­‐‑
ty), show an average of fewer than two overflow events a
year, and this period includes 2008, which had the largest
recorded rainfall in the Chicago area’s history. The district
court was entitled to think a wait-­‐‑and-­‐‑see approach reason-­‐‑
able. The best way to decide between competing predictions
is to see what happens.
But the Alliance maintains that the consent decree itself
concedes that the system won’t work. That is because the de-­‐‑
cree authorizes untreated discharges when (a) the tunnels
are full, or (b) a “transient event” occurs—roughly, when the
rate of inflow is so great that allowing it to continue would
damage the tunnel system, and the District must close one or
more gates to protect it. The Alliance says that this will occur
whenever there is a “heavy rainstorm” but does not quantify
that term (how heavy? how often? how much untreated wa-­‐‑
ter will be discharged?). More important, however, is the
structure of the Clean Water Act: discharges are forbidden
except when authorized. If the EPA and the Pollution Con-­‐‑

-- 9 of 13 --

10 Nos. 14-­‐‑1776 & 14-­‐‑1777
trol Board are willing to authorize untreated discharges
when there is no alternative (and that’s what conditions (a)
and (b) amount to), then there’s no violation of the Act.
It’s not as if the Alliance were contending that the tunnel
system itself should be enlarged or its design changed, long
after its construction, to avoid damage from particularly
large inflows. Water weighs 62.4 pounds per cubic foot, or 8
pounds a gallon, and can drop a long distance in the tunnel
system—greater than the height of Niagara Falls, where
dropping water generates vast quantities of energy. This
shows the power of gravity and the need to protect even
tunnels with thick concrete walls. The consent decree allows
the District to protect this costly pollution-­‐‑control asset.
In the district court, the Alliance proposed that the Dis-­‐‑
trict build treatment plants at 105 outfalls, increasing the
number of plants from 7 large ones to 112 mostly small
ones—just in case. But the district judge sensibly concluded
that it would be imprudent to spend $1 billion on that pro-­‐‑
ject if it turns out that the system will be largely effective
when the reservoirs are completed, for by the time the 105
new plants were operational they might be unnecessary. The
Alliance’s appellate brief drops this proposal, leaving no al-­‐‑
ternative to the decree’s toleration of the inevitable.
The Alliance’s final argument that the decree won’t work
is that it permits the release of floatables in excess of the
quantity allowed by the “Combined Sewer Overflow Con-­‐‑
trol Policy” adopted by the EPA in 1994. See 59 Fed. Reg.
18,688 (Apr. 19, 1994). The district court found otherwise,
concluding that after the Deep Tunnel system is complete
the District will be in compliance with the floatables policy.
That finding is not clearly erroneous. If the Chicago area had

-- 10 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 11
a different kind of sewer system, or if Deep Tunnel had been
designed differently, then a consent decree might have been
able to achieve full compliance faster. That the settlement of
a given case takes the world as it exists, however, does not
show a lack of diligent prosecution or a substantively unrea-­‐‑
sonable outcome.
The EPA and the State sought to deal with the limitations
imposed by the design of the sewer system and the Deep
Tunnel project by using realistically available options. The
District already has two pontoon boats that deal with floata-­‐‑
bles; the decree requires it to add two specially designed
skimmer boats to keep floatables under control (even if their
source is something other than the District’s system) and to
put a boom around one outfall that has experienced frequent
discharges. (Booms elsewhere might interfere with naviga-­‐‑
tion.) Another part of the decree requires the District to
adopt a “green infrastructure” program that will reduce the
amount of water flowing into the system during rains. The
District must supply rain barrels to catch runoff from build-­‐‑
ings and increase the permeability of the surface so that the
ground can retain more water. The District must complete
the reservoirs on schedule and pay as much as $5,000 a day
for failure to do so; a desire to avoid these fines may lead the
District to pay the limestone miners to remove the rock fast-­‐‑
er. Once each of the new reservoirs is completed, the District
must provide enough on-­‐‑site water treatment capacity to
cover “the maximum flow accounting for all hydraulic and
hydrologic factors that can pass through” the system. It must
provide extra pumps if needed to move water faster from
reservoirs to treatment plants, so that storage capacity is
available in the reservoirs for incoming water. And if moni-­‐‑
toring reveals that these steps don’t achieve their goal, then

-- 11 of 13 --

12 Nos. 14-­‐‑1776 & 14-­‐‑1777
the District must come up with and implement a new plan
that will. These are costly promises by the District, and the
district court did not abuse its discretion (the applicable
standard, see United States v. George A. Whiting Paper Co., 644
F.3d 368, 372 (7th Cir. 2011)) in concluding that the decree
carries a reasonable prospect of success.
As the Alliance sees things, some of the District’s prom-­‐‑
ises are worthless (or at least incomplete) because the decree
does not spell out “which pollutants will be monitored, at
which locations, how frequently, or by what method.” And
it does not specify what, precisely, will be done if problems
remain in 2029. Some other consent decrees that the EPA has
negotiated do include these things. Yet the District is so
large, and the locations of potential outfalls so numerous,
that it’s just not practical to try to cover all details in one
document. The EPA anticipates working out details as time
passes and additional reservoir capacity becomes available
(which influences what needs to be looked at and tested for),
and if the District does not cooperate the court can afford
supplemental relief.
As for what happens in 2029 or later if untreated dis-­‐‑
charges continue at an unacceptable rate, the next steps
ought to depend on what’s not then working well. If the
EPA (or a court) could be sure in 2014 what the exact nature
of the problem (if any) would be in 2029, then it would be
sensible to start planning and building the remedy today;
but if either there won’t be a serious problem in 2029, or the
problem is something not now foreseen, then relying on a
2014 decree for the solution would be foolish. Yogi Berra ob-­‐‑
served that it is hard to make predictions, especially about

-- 12 of 13 --

Nos. 14-­‐‑1776 & 14-­‐‑1777 13
the future. State and federal agencies are entitled to rely
more on experience and less on predictions.
The consent decree that the district court has approved is
reasonable in light of the current infrastructure, the costs of
doing things differently (no one proposes to build a new
sewer system or redo the Deep Tunnel project), and the lim-­‐‑
its of knowledge about what will happen when the system is
completed. The decree is the outcome of diligent prosecution
and therefore binds would-­‐‑be private litigants such as the
Alliance.
AFFIRMED

-- 13 of 13 --