Florida v. Georgia

P R E L I M I N A R Y P R I N T
Volume 592 U. S. Part 2
Pages 433–444
OFFICIAL REPORTS
OF
T H E S U P R E M E C O U R T
April 1, 2021
REBECCA A. WOMELDORF
reporter of decisions
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N O T I C E : This preliminary print is subject to formal revision before
the bound volume is published. Users are requested to notify the Reporter
of Decisions, Supreme Court of the United States, Washington, D.C. 20543,
pio@supremecourt.gov, of any typographical or other formal errors.

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OCTOBER
TERM, 2020
433
Syllabus
FLORIDA v. GEORGIA
on
exceptions to second report of special master
No. 142, Orig. Argued February 22, 2021—Decided April 1, 2021
This case involves a dispute between Florida and Georgia concerning
the proper apportionment of interstate waters. Florida brought an
original action against Georgia alleging that its upstream neighbor
consumes more than its fair share of water from interstate rivers in
the Apalachicola-Chattahoochee-Flint River Basin. Florida claims that
Georgia's overconsumption of Basin waters caused low fows in the Apa-
lachicola River which seriously harmed Florida's oyster fsheries and
river ecosystem. The frst Special Master appointed by the Court to
assess Florida's claims recommended dismissal of Florida's complaint.
The Court disagreed with the Special Master's analysis of the threshold
question of redressability, and remanded for the Special Master to make
defnitive fndings and recommendations on several issues, including:
whether Florida had proved any serious injury caused by Georgia; the
extent to which reducing Georgia's water consumption would increase
Apalachicola River fows; and the extent to which any increased Apa-
lachicola fows would redress Florida's injuries. Florida v. Georgia,
585 U. S. –––. Following supplemental briefng and oral argument, the
Special Master then reviewing the case produced an 81-page report rec-
ommending that the Court deny Florida relief. Relevant here, the Spe-
cial Master concluded that Florida failed to prove by clear and convinc-
ing evidence that Georgia's alleged overconsumption caused serious
harm either to Florida's oyster fsheries or to its river wildlife and plant
life. Florida fled exceptions.
Held: Florida's exceptions to the Special Master's Report are overruled,
and the case is dismissed. Pp. 438–444.
(a) The Court has original jurisdiction to equitably apportion inter-
state waters between States. Given the competing sovereign interests
in such cases, a complaining State bears a burden much greater than
does a private party seeking an injunction. Florida concedes that it
cannot obtain an equitable apportionment here unless it frst proves by
clear and convincing evidence a serious injury caused by Georgia. The
Court conducts an independent review of the record in ruling on Flori-
da's exceptions to the Special Master's Report. Kansas v. Nebraska,
574 U. S. 445, 453. Pp. 438–439.
(b) Florida has not proved by clear and convincing evidence that the
collapse of its oyster fsheries was caused by Georgia's overconsumption.

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434 FLORID
A v. GEORGIA
Syllabus
The oyster population in the Bay collapsed in 2012 in the midst of a
se
vere drought. Florida attempts to show that Georgia's alleged unrea-
sonable agricultural water consumption caused reduced river fows,
which in turn increased the Bay's salinity, which in turn attracted salt-
water oyster predators and disease, decimating the oyster population.
Georgia offers contrary evidence that Florida's mismanagement of its
fsheries, rather than reduced river fows, caused the decline. Florida's
own documents and witnesses reveal that Florida allowed unprece-
dented levels of oyster harvesting in the years leading to the collapse.
And the record points to other potentially relevant factors, including
actions of the U. S. Army Corps of Engineers, multiyear droughts, and
changing rainfall patterns. The precise causes of the Bay's oyster col-
lapse remain a subject of scientifc debate, but the record evidence es-
tablishes at most that increased salinity and predation contributed to
the collapse of Florida's fsheries, not that Georgia's overconsumption
caused the increased salinity and predation. Florida fails to establish
that Georgia's overconsumption was a substantial factor contributing to
its injury, much less the sole cause. As such the Court need not address
the causation standard applicable in equitable-apportionment cases.
Pp. 439–443.
(c) Florida also has not proved by clear and convincing evidence that
Georgia's overconsumption has harmed river wildlife and plant life by
disconnecting tributaries, swamps, and sloughs from the Apalachicola
River, thereby drying out important habitats for river species. The
Special Master found “a complete lack of evidence” that any river spe-
cies has suffered or will suffer serious injury from Georgia's alleged
overconsumption, Second Report of Special Master 22, and the Court
agrees with that conclusion. Pp. 443–444.
Exceptions overruled, and case dismissed.
Barrett, J., delivered the opinion for a unanimous Court.
Gregory G. Garre argued the cause for plaintiff. With
him on the brief were Ashley Moody, Attorney
General of Florida, Amit Agarwal, Solicitor General, Philip
J. Perry, Jamie L. Wine, and Abid R. Qureshi.
Crai g S. Pr imis arg ued the cause for defendant.
With him on the brief were Christopher M. Carr, Attorney
Genera l of Georg ia, Andrew P in so n, Solicitor Genera l,

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as: 592 U. S. 433 (2021)
435
Opinion of the Court
K. Winn All en, Devo ra W. All o n, and L auren N.
Beebe.
*
Justice Barrett delivered the opinion of the Court.
For the second time in three years, we confront a dispute
between Florida and Georgia over the proper apportionment
of i nterst ate waters. Flor ida, the downstream St ate,
brought this original action against Georgia, claiming that
Georgia consumes more than its fair share of water from an
interstate network of rivers. Florida says that Georgia's
overconsumption harms its economic and ecological inter-
ests, and it seeks a decree requiring Georgia to reduce its
consumption.
When the case was last before the Court, we resolved it
narrowly and remanded to a Special Master with instruc-
tions to make fndings and recommendations on additional
issues. Florida v. Georgia, 585 U. S. ––– (2018). On re-
mand, the Special Master recommended that we deny Flor-
ida relief for several independent reasons, including that
Florida proved no serious injury caused by Georgia's al-
leged overconsumption.
Based on our independent review of the record, we agree
with the Special Master's recommendation. We therefore
overrule Florida's exceptions to the Special Master's Report
and dismiss the case.
I
This case concerns the Apalachicola-Chattahoochee-Flint
River Basin, an area spanning more than 20,000 square miles
in Georgia, Florida, and Alabama. The Basin contains three
*Briefs of amici curiae were fled for the United States by Acting Solic-
itor General Wall, Deputy Solicitor General Kneedler, Deputy Assistant
Attorney General Grant, Frederick Liu, and Michael T. Gray; for the
Atlanta Regional Commission et al. by Lewis B. Jones; and for Franklin
County, Florida Seafood Workers by Lisa S. Blatt.
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436 FLORID
A v. GEORGIA
Opinion of the Court
rivers. The Chattahoochee River and the Flint River start
i
n Georgia and empty into Lake Seminole, which straddles
the Georgia-Florida border. Both rivers are critical sources
of water for Georgia. The Chattahoochee is the primary
water supply for the Atlanta metropolitan area, while the
Flint supplies irrigation to southwestern Georgia's agricul-
tural industry.
The third river in the Basin is the Apalachicola River. It
starts from the southern end of Lake Seminole and fows
south through the Florida Panhandle, emptying into the Ap-
alachicola Bay (Bay), near the Gulf of Mexico. The Apalach-
icola River supports a wide range of river wildlife and plant
life in the Florida Panhandle, and its steady supply of fresh
water makes the Bay a suitable habitat for oysters. For
many years, Florida's oyster fsheries were a cornerstone of
the regional economy.
Many factors infuence Apalachicola River fows, including
precipitation, air temperature, and Georgia's upstream con-
sumption of Basin waters. The U. S. Army Corps of Engi-
neers also plays an important role. The Corps regulates
Apalachicola fows by storing water in, and releasing water
from, its network of reservoirs in the Basin. In recent
years, low fows in the Apalachicola River have become in-
creasingly common during the dry summer and fall months,
particularly during droughts.
In 2013, on the heels of the third regional drought in just
over a decade, Florida brought this original action against
Georgia, seeking an equitable apportionment of the Basin
waters. See 28 U. S. C. § 1251(a); U. S. Const., Art. III, § 2.
Florida asserts that Georgia's overconsumption of Basin wa-
ters causes sustained low fows in the Apalachicola River,
which in turn harm its oyster fsheries and river ecosystem.
As a remedy, Florida seeks an order requiring Georgia to
reduce its consumption of Basin waters. Florida does not
seek relief against the Corps.
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437
Opinion of the Court
We granted Florida leave to fle its complaint and referred
the
case to Special Master Ralph Lancaster, Jr. After 18
months of extensive discovery and a 5-week trial, the Special
Master issued a report recommending that Florida be denied
relief. Although the Special Master assumed for the sake of
his analysis that Florida had suffered serious injuries due
to Georgia's upstream water use, he determined that it was
unnecessary to make defnitive fndings on those issues be-
cause Florida failed to prove by clear and convincing evi-
dence that any remedy would redress its asserted injuries.
That was so because a remedial decree would not bind the
Corps, which could operate its reservoirs to offset any added
streamfow produced by the decree.
On review of Florida's exceptions to the Special Master's
Report, we remanded for further proceedings. Florida v.
Georgia, 585 U. S. –––. We concluded that the Special
Master's clear and convincing evidence standard for the
“ `threshold' ” question of redressability was “too strict,” at
least absent further fndings. Id., at ––– – –––. We then di-
rected the Special Master to make defnitive fndings and
recommendations on several additional issues, including:
whether Florida had proved any serious injury caused by
Georgia; the extent to which reducing Georgia's water con-
sumption would increase Apalachicola River fows; and the
extent to which any increased Apalachicola fows would re-
dress Florida's injuries. Id., at ––– – –––.
Soon after our decision in Florida, Special Master Lancas-
ter retired, and we appointed Judge Paul Kelly as the Special
Master. Following supplemental briefng and oral argu-
ment, Special Master Kelly issued an 81-page report re-
commending, for several independent reasons, that this
Court deny Florida relief. Relevant here, the Special Mas-
ter concluded that Florida failed to prove by clear and con-
vincing evidence that Georgia's alleged overconsumption
caused serious harm to Florida's oyster fsheries or its river
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438 FLORID
A v. GEORGIA
Opinion of the Court
wildlife and plant life. Second Report of Special Master
8
–25.
Florida again fled exceptions to the Special Master's Re-
port. We must “conduct an independent review of the rec-
ord, and assume the ultimate responsibility for deciding all
matters.” Kansas v. Nebraska, 574 U. S. 445, 453 (2015) (in-
ternal quotation marks omitted). Having done so, we over-
rule Florida's exceptions and adopt the Special Master's
recommendation.
II
“This Court has recognized for more than a century its
inherent authority, as part of the Constitution's grant of orig-
inal jurisdiction, to equitably apportion interstate streams
between States.” Id., at 454. Given the weighty and com-
peting sovereign interests at issue in these cases, “a com-
plaining State must bear a burden that is `much greater' than
the burden ordinarily shouldered by a private party seeking
an injunction.” Florida, 585 U. S., at –––.
Here, Florida must make two showings to obtain an equi-
table apportionment. First, Florida must prove a threat-
ened or actual injury “of serious magnitude” caused by Geor-
gia's upstream water consumption. See id., at –––, –––
(internal quotation marks omitted); Colorado v. New Mexico,
459 U. S. 176, 187, n. 13 (1982) (Colorado I). Second, Florida
must show that “the benefts of the [apportionment] substan-
tially outweigh the harm that might result.” Id., at 187.
Because Florida and Georgia are both riparian States, the
“guiding principle” of this analysis is that both States have
“an equal right to make a reasonable use” of the Basin wa-
ters. Florida, 585 U. S., at ––– (emphasis deleted; internal
quotation marks omitted).
To resolve this case, we need address only injury and cau-
sation. Florida asserts that Georgia's overconsumption of
Basin waters caused it two distinct injuries: the collapse of
its oyster fsheries and harm to its river ecosystem. Florida
does not dispute that it must prove injury and causation by
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439
Opinion of the Court
clear and convincing evidence. See Colorado I, 459 U. S., at
187,
n. 13. To do so, Florida must “place in the ultimate
factfnder an abiding conviction that the truth of its factual
contentions are `highly probable.' ” Colorado v. New Mex-
ico, 467 U. S. 310, 316 (1984) (Colorado II).
With Florida's heavy burden in mind, we address its as-
serted injuries in turn.
A
In 2012, in the midst of a severe drought, the oyster popu-
lation in the Apalachicola Bay collapsed, causing commercial
oyster sales to plummet. By the time of trial, the Bay's
fsheries had yet to recover. All agree that this is an injury
“of serious magnitude” under our equitable-apportionment
precedents. See New York v. New Jersey, 256 U. S. 296,
309 (1921).
The parties, however, offer competing explanations for the
cause of the collapse. Florida pins the collapse on Georgia
through a multistep causal chain. It argues that Georgia's
unreasonable agricultural water consumption caused sus-
tained low fows in the Apalachicola River; that these low
fows increased the Bay's salinity; and that higher salinity in
the Bay attracted droves of saltwater oyster predators and
disease, ultimately decimating the oyster population.
Georgia points to a more direct cause—Florida's misman-
agement of its oyster fsheries. According to Georgia, Flor-
ida caused the collapse by overharvesting oysters and failing
to replace harvested oyster shells. And even if low fows
contributed at all, Georgia says, they were driven by climatic
changes and other factors, not its upstream consumption.
Of course, the precise causes of the Bay's oyster collapse
remain a subject of ongoing scientifc debate. As judges, we
lack the expertise to settle that debate and do not purport to
do so here. Our more limited task is to evaluate the parties'
arguments in light of the record evidence and Florida's heavy
burden of proof. And on this record, we agree with the Spe-
cial Master that Florida has failed to carry its burden.
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440 FLORID
A v. GEORGIA
Opinion of the Court
Florida's own documents and witnesses reveal that Florida
a
llowed unprecedented levels of oyster harvesting in the
years before the collapse. In 2011 and 2012, oyster harvests
from the Bay were larger than in any other year on record.
Fla. Exh. 839; 4 Trial Tr. 956; 6 Trial Tr. 1391. That was in
part because Florida loosened various harvesting restric-
tions out of fear—ultimately unrealized—that the Deepwater
Horizon oil spill would contaminate its oyster fsheries. 3
Trial Tr. 767–769. A former Florida offcial, one of Florida's
lead witnesses, acknowledged that these management prac-
tices “ `bent' ” Florida's fsheries “ `until [they] broke.' ” Ga.
Exh. 1357, p. 1; 4 Trial Tr. 877.
The record also shows that Florida failed to adequately
reshell its oyster bars. Reshelling is a century-old oyster-
management practice that involves replacing harvested oys-
ter shells with clean shells, which can serve as habitat for
young oysters. Id., at 907–908; 17 Trial Tr. 4390. Yet in
the years before the collapse, while Florida was harvesting
oysters at a record pace, it was simultaneously reshelling its
oyster bars at a historically low rate. See Direct Testimony
of Romuald N. Lipcius ¶¶138–151 (Lipcius), and Demos. 15,
16; see also Ga. Exh. 568, p. 5 (recommending that Florida
reshell 200 acres per year); 7 Trial Tr. 1692 (Florida reshelled
180 total acres in the 10 years before the collapse).
Georgia's marine ecologist, Dr. Lipcius, demonstrated the
stark effects of Florida's increased harvesting and lax re-
shelling efforts. Analyzing data on oyster densities precol-
lapse and postcollapse, Dr. Lipcius found that mean densities
in the Bay's most heavily harvested oyster bars dropped by
an average of 78%, while mean densities increased by 3% to
13% at bars that either were not heavily harvested or had
been reshelled. Lipcius ¶¶41–44. Dr. Lipcius also found
negligible differences in salinity among the bars that he ana-
lyzed, suggesting that increased salinity did not explain the
variance in oyster densities. Id., ¶¶48–51.
Flor ida does not meani ng fu l ly rebut th is ev idence.
Yet Florida nonetheless argues that Georgia's overconsump-
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441
Opinion of the Court
tion—and the consequent increased salinity and predation—
was
the sole cause of the collapse, or at least a substantial
factor contributing to it.* But here again, Florida's own
witnesses suggest otherwise.
Dr. White, one of Florida's ecology experts, modeled how
oyster biomass would have changed at two of the Bay's major
oyster bars if Georgia had consumed less water in the years
leading up to the collapse. His modeling showed that reduc-
ing Georgia's consumption by an amount “similar to the relief
that Florida is requesting ” in this case would have increased
oyster biomass by less than 1.5% in 2012. Updated Pre-
Filed Direct Testimony (PFDT) of J. Wilson White 49–51,
fgs. 14, 15.
Florida does not explain how such minor fuctuations in
oyster biomass could have averted the collapse. Instead,
Florida points to testimony that increased streamfow would
have had “larger” effects on oyster biomass at oyster bars
closer to the river's mouth. 7 Trial Tr. 1725; see also id., at
1868–1870. But it was Florida's burden to quantify how
much larger the effects would have been, and its experts did
not model biomass changes at bars near the river. See 6
Trial Tr. 1571.
Other Florida experts reinforced Dr. White's biomass
fndings. One expert found that salinity reductions of
greater than 10 parts per thousand are “required” in order to
reduce predation by rock snails—one of the oyster's fercest
predators. Fla. Exh. 797, p. 38; Updated PFDT of Mark
Berrigan ¶¶42–43 (Berrigan). Yet according to another
Florida expert, salinity throughout the Bay would have de-
clined by substantially less than 10 parts per thousand in
2012 even if Georgia had eliminated all of its consumption
from the Basin. PFDT of Marcia Greenblatt ¶¶4, 27,
30. Together, these fndings further undermine the asserted
*We have not specifed the causation standard applicable in equitable-
apportionment cases. We need not do so here, for Florida has failed to
establish a suffcient causal connection under any of the parties' proposed
standards.

442 FLORID
A v. GEORGIA
Opinion of the Court
link between Georgia's consumption and decreased oyster
bi
omass.
In response to this empirical evidence, Florida relies pri-
marily on: (1) testimony from a local oysterman and a former
Florida offcial that they witnessed high salinity and signif-
cant oyster predation, including at private oyster bars not
subject to overharvesting, PFDT of Thomas L. Ward ¶¶33–
37; Berrigan ¶¶44–48; (2) reports by its own agency blaming
the collapse in part on salinity and predation, Joint Exhs. 50,
77; (3) a fshery-disaster declaration by the National Oceanic
and Atmospheric Administration (NOAA) adopting the con-
clusion of Florida's agency, Fla. Exh. 413, p. 3; and (4) feld
experiments conducted by one of Florida's experts in the
years after the collapse, which purport to demonstrate a link
between increased salinity and predation, Updated PFDT of
David Kimbro ¶¶63–90.
The fundamental problem with this evidence—a problem
that pervades Florida's submission in this case—is that it
establishes at most that increased salinity and predation con-
tributed to the collapse, not that Georgia's overconsumption
caused the increased salinity and predation. None of these
witnesses or reports point to Georgia's overconsumption as
a signifcant cause of the high salinity and predation. The
NOAA, in fact, primarily blamed “prolonged drought condi-
tions” and the Corps' reservoirs operations—not Georgia's
consumption during drought conditions—for the elevated
levels of salinity and predation in the Bay. Fla. Exh. 413,
pp. 3–4. Other record evidence, moreover, indicates that
the unprecedented series of multiyear droughts, as well as
changes in seasonal rainfall patterns, may have played a sig-
nifcant role. See PFDT of Dennis Lettenmaier 17, fg. 8;
Direct Testimony of Wei Zeng ¶¶144–152. Given these con-
founding factors, we do not think that Florida's evidence of
high salinity and predation overcomes the data and modeling
of its own experts, which show that Georgia's consumption
had little to no impact on the Bay's oyster population.
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Opinion of the Court
Considering the record as a whole, Florida has not shown
that
it is “highly probable” that Georgia's alleged overcon-
sumption played more than a trivial role in the collapse of
Florida's oyster fsheries. See Colorado II, 467 U. S., at 316.
Florida therefore has failed to carry its burden of proving
causation by clear and convincing evidence.
B
Florida also argues that Georgia's overconsumption has
harmed river wildlife and plant life by disconnecting tribu-
taries, swamps, and sloughs from the Apalachicola River,
thereby drying out important habitats for river species.
The Special Master found “a complete lack of evidence” that
any river species suffered serious injury from Georgia's al-
leged overconsumption, and we agree. Second Report of
Special Master 22.
In seeking to prove injury, Florida relied primarily on
species-specifc “harm metrics” developed by Dr. Allan, one
of its ecology experts. Dr. Allan established minimum
river-fow regimes that he believed necessary for certain
species of fsh, mussels, and trees to avoid “signifcant harm”
during dry months. Updated PFDT of J. David Allan ¶¶33–
61 (Allan). He then sought to quantify the harm to each
species by totaling the number of days in which river fows
fell below his thresholds. Id., ¶¶62–63.
What Dr. Allan did not do, however, is show that his harm
metrics did or likely would translate into real-world harm to
the species that he studied. Indeed, Dr. Allan provided no
data showing that the overall population of any river species
has declined in recent years. See 2 Trial Tr. 389–392, 395–
396. And other evidence casts signifcant doubt on Dr. Al-
lan's harm metrics. For instance, the U. S. Fish & Wildlife
Service found that the population of the fat threeridge
mussel—one of the species Dr. Allan analyzed—“appears sta-
ble and may be increasing in size.” Joint Exh. 168, p. 125;
Allan ¶42.
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444 FLORID
A v. GEORGIA
Opinion of the Court
Without stronger evidence of actual past or threatened
har
m to species in the Apalachicola River, we cannot fnd it
“highly probable” that these species have suffered serious
injury, let alone as a result of any overconsumption by Geor-
gia. See Colorado II, 467 U. S., at 316.
***
In short, Florida has not met the exacting standard neces-
sary to warrant the exercise of this Court's extraordinary
authority to control the conduct of a coequal sovereign. We
emphasize that Georgia has an obligation to make reasonable
use of Basin waters in order to help conserve that increas-
ingly scarce resource. But in light of the record before us,
we must overrule Florida's exceptions to the Special
Master's Report and dismiss the case.
It is so ordered.
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