       COUR INTERNATIONALE DE JUSTICE

           RECUEIL DES ARRE| TS,
    AVIS CONSULTATIFS ET ORDONNANCES

FFAIRE RELATIVE Av DES USINES DE PÂTE
 Av PAPIER SUR LE FLEUVE URUGUAY
         (ARGENTINE c. URUGUAY)

           ARRE
              | T DU 20 AVRIL 2010

               2010
        INTERNATIONAL COURT OF JUSTICE

         REPORTS OF JUDGMENTS,
      ADVISORY OPINIONS AND ORDERS

   CASE CONCERNING PULP MILLS
     ON THE RIVER URUGUAY
         (ARGENTINA v. URUGUAY)

         JUDGMENT OF 20 APRIL 2010

                     Mode officiel de citation :
sines de pâte à papier sur le fleuve Uruguay (Argentine c. Uruguay),
                  arrêt, C.I.J. Recueil 2010, p. 14

                        Official citation :
    Pulp Mills on the River Uruguay (Argentina v. Uruguay),
              Judgment, I.C.J. Reports 2010, p. 14

                                          Sales number
SN 0074-4441
BN 978-92-1-071089-3
                                          No de vente :   977

                                    20 AVRIL 2010

                                        ARRE
                                           |T

USINES DE PA
           | TE A
                v PAPIER SUR LE FLEUVE URUGUAY
           (ARGENTINE c. URUGUAY)

      PULP MILLS ON THE RIVER URUGUAY
           (ARGENTINA v. URUGUAY)

                                     20 APRIL 2010

                                     JUDGMENT

                      TABLE OF CONTENTS
                                                                   Paragraphs

RONOLOGY OF THE PROCEDURE                                               1-24
. LEGAL FRAMEWORK AND FACTS OF THE CASE                                25-47
 A. Legal framework                                                    26-27
 B. CMB (ENCE) Project                                                 28-36
 C. Orion (Botnia) mill                                                37-47
. SCOPE OF THE COURT’S JURISDICTION                                    48-66
. THE ALLEGED BREACH OF PROCEDURAL OBLIGATIONS                        67-158
 A. The links between the procedural obligations and the sub-
    stantive obligations                                               71-79
 B. The procedural obligations and their interrelation                80-122
     1. The nature and role of CARU                                    84-93
     2. Uruguay’s obligation to inform CARU                           94-111
     3. Uruguay’s obligation to notify the plans to the other
        party                                                        112-122
 C. Whether the Parties agreed to derogate from the procedural
    obligations set out in the 1975 Statute                          123-150
     1. The “understanding” of 2 March 2004 between Argen-
        tina and Uruguay                                             125-131
     2. The agreement setting up the High-Level Technical
        Group (the GTAN)                                             132-150
 D. Uruguay’s obligations following the end of the negotiation
    period                                                           151-158
. SUBSTANTIVE OBLIGATIONS                                            159-266
 A. Burden of proof and expert evidence                              160-168
 B. Alleged violations of substantive obligations                    169-266
     1. The obligation to contribute to the optimum and rational
        utilization of the river (Article 1)                         170-177
     2. The obligation to ensure that the management of the soil
        and woodland does not impair the régime of the river or
        the quality of its waters (Article 35)                       178-180
     3. The obligation to co-ordinate measures to avoid changes
        in the ecological balance (Article 36)                       181-189
     4. The obligation to prevent pollution and preserve the
        aquatic environment (Article 41)                             190-266
       (a) Environmental Impact Assessment                           203-219
             (i) The siting of the Orion (Botnia) mill at Fray
                 Bentos                                              207-214
            (ii) Consultation of the affected populations            215-219

                                                                           4

       (b) Question of the production technology used in the
           Orion (Botnia) mill                                     220-228
       (c) Impact of the discharges on the quality of the waters
           of the river                                            229-259
              (i) Dissolved oxygen                                 238-239
             (ii) Phosphorus                                       240-250
            (iii) Phenolic substances                              251-254
            (iv) Presence of nonylphenols in the river environ-
                  ment                                             255-257
             (v) Dioxins and furans                                258-259
       (d) Effects on biodiversity                                 260-262
       (e) Air pollution                                           263-264
       (f) Conclusions on Article 41                                   265
       (g) Continuing obligations : monitoring                         266
. THE CLAIMS MADE BY THE PARTIES IN THEIR FINAL SUBMISSIONS        267-281

PERATIVE CLAUSE                                                       282

                                                                        5

                ABBREVIATIONS AND ACRONYMS

AP            “Autorización Ambiental Previa” (initial environmental
              authorization)
DCP           Acoustic Doppler Current Profiler
OX            Adsorbable Organic Halogens
AT            Best Available Techniques (or Technology)
 tnia         “Botnia S.A.” and “Botnia Fray Bentos S.A.” (two companies
              formed under Uruguayan law by the Finnish company Oy
              Metsä-Botnia AB)
ARU           “Comisión Administradora del Río Uruguay” (Administrative
              Commission of the River Uruguay)
 S            Cumulative Impact Study (prepared in September 2006 at the
              request of the International Finance Corporation)
MB            Celulosas de M’Bopicuá S.A.” (a company formed under Uru-
              guayan law by the Spanish company ENCE)
MB (ENCE) Pulp mill planned at Fray Bentos by the Spanish company
              ENCE, which formed the Uruguayan company CMB for that
              purpose
 NAMA         “Dirección Nacional de Medio Ambiente” (National Directo-
              rate for the Environment of the Uruguayan Government)
CF            Elemental Chlorine-Free
 A            Environmental Impact Assessment
NCE           “Empresa Nacional de Celulosas de España” (Spanish com-
              pany which formed the company CMB under Uruguayan law)
 AP           Environmental and Social Action Plan
TAN           “Grupo Técnico de Alto Nivel” (High-Level Technical Group
              established in 2005 by Argentina and Uruguay to resolve their
              dispute over the CMB (ENCE) and Orion (Botnia) mills)
 C            International Finance Corporation
PC-BAT        Integrated Pollution Prevention and Control Reference Docu-
              ment on Best Available Techniques in the Pulp and Paper
              Industry
 VOTMA        “Ministerio de Vivienda, Ordenamiento Territorial y Medio
              Ambiente” (Uruguayan Ministry of Housing, Land Use Plan-
              ning and Environmental Affairs)
 ion (Botnia) Pulp mill built at Fray Bentos by the Finnish company Oy
              Metsä-Botnia AB, which formed the Uruguayan companies
              Botnia S.A. and Botnia Fray Bentos S.A. for that purpose
  E           “Obras Sanitarias del Estado” (Uruguay’s State Agency for
              Sanitary Works)
OPs           Persistent Organic Pollutants
ROCEL         “Plan de Monitoreo de la Calidad Ambiental en el Río Uru-
              guay en áreas de Plantas Celulósicas” (Plan for monitoring
              water quality in the area of the pulp mills set up under CARU)

                                                                          6

ROCON   “Programa de Calidad de Aguas y Control de la Contami-
        nación del Río Uruguay” (Water quality and pollution control
        programme set up under CARU)

                                                                  7

             INTERNATIONAL COURT OF JUSTICE

                               YEAR 2010                                              2010
                                                                                20 April
                                                                                General List
                               20 April 2010                                        No. 135

        CASE CONCERNING PULP MILLS
          ON THE RIVER URUGUAY
                    (ARGENTINA v. URUGUAY)

Legal framework and facts of the case.
1961 Treaty of Montevideo — 1975 Statute of the River Uruguay — Estab-
hment of the Administrative Commission of the River Uruguay (CARU) —
MB (ENCE) pulp mill project — Orion (Botnia) pulp mill project — Port
minal at Nueva Palmira — Subject of the dispute.

                                      *
Scope of the Court’s jurisdiction.
Compromissory clause (Article 60 of the 1975 Statute) — Provisions of the
75 Statute and jurisdiction ratione materiae — Lack of jurisdiction for the
urt to consider allegations concerning noise and visual pollution or bad
ours (Article 36 of the 1975 Statute) — Air pollution and impact on the qual-
 of the waters of the river addressed under substantive obligations.

Article 1 of the 1975 Statute — Definition of the purpose of the 1975 Stat-
  — Joint machinery necessary for the optimum and rational utilization of the
er — Significance of the reference to the “rights and obligations arising from
aties and other international agreements in force for each of the parties” —
iginal Spanish text — Statute adopted by the parties in observance of their
 pective international commitments.
Article 41 (a) of the 1975 Statute — Original Spanish text — Absence of a
 ferral clause” having the effect of incorporating within the ambit of the Stat-
  the obligations of the parties under international agreements and other
rms envisaged in the Statute — Obligation for the parties to exercise their
 ulatory powers, in conformity with applicable international agreements, for
  protection and preservation of the aquatic environment of the River Uru-
ay — Rules for interpreting the 1975 Statute — Article 31 of the Vienna

                                                                              8

 nvention on the Law of Treaties — Distinction between taking account of
her international rules in the interpretation of the 1975 Statute and the scope
 the jurisdiction of the Court under Article 60 of the latter.

                                      *
Alleged breach of procedural obligations.
Question of links between the procedural obligations and the substantive obli-
tions — Object and purpose of the 1975 Statute — Optimum and rational
 lization of the River Uruguay — Sustainable development — Co-operation
  ween the parties in jointly managing the risks of damage to the environ-
 nt — Existence of a functional link, in regard to prevention, between the pro-
dural obligations and the substantive obligations — Responsibility in the event
 breaches of either category.
Interrelation of the various procedural obligations laid down by Articles 7 to
  of the 1975 Statute — Original Spanish text of Article 7 — Obligation to
 orm, notify and negotiate as an appropriate means of achieving the objective
 optimum and rational utilization of the river as a shared resource — Legal
  sonality of CARU — Central role of CARU in the joint management of the
 er and obligation of the parties to co-operate.
Obligation to inform CARU (Article 7, first paragraph, of the 1975 Stat-
  ) — Works subject to this obligation — Link between the obligation to
 orm CARU, co-operation between the parties and the obligation of preven-
 n — Determination by CARU on a preliminary basis of whether there is a
k of significant damage to the other party — Content of the information to be
 nsmitted to CARU — Obligation to inform CARU before issuing of the ini-
 l environmental authorization — Provision of information to CARU by pri-
  e operators cannot substitute for the obligation to inform laid down by the
75 Statute — Breach by Uruguay of the obligation to inform CARU.
Obligation to notify the plans to the other party (Article 7, second and third
ragraphs, of the 1975 Statute) — Need for a full environmental impact
  essment (EIA) — Notification of the EIA to the other party, through
ARU, before any decision on the environmental viability of the plan — Breach
  Uruguay of the obligation to notify the plans to Argentina.

Question of whether the Parties agreed to derogate from the procedural obli-
tions — “Understanding” of 2 March 2004 — Content and scope — Since
uguay did not comply with it, the “understanding” cannot be regarded as
ving had the effect of exempting Uruguay from compliance with the proce-
ral obligations — Agreement setting up the High-Level Technical Group
 TAN) — Referral to the Court on the basis of Article 12 or Article 60 of the
75 Statute : no practical distinction — The agreement to set up the GTAN
d the aim of enabling the negotiations provided for in Article 12 of the 1975
atute to take place, but did not derogate from other procedural obligations —
accepting the creation of the GTAN, Argentina did not give up the procedural
hts belonging to it by virtue of the Statute, nor the possibility of invoking
uguay’s responsibility ; nor did Argentina consent to suspending the operation
the procedural provisions of the Statute (Article 57 of the Vienna Convention
 the Law of Treaties) — Obligation to negotiate in good faith — “No con-
uction obligation” during the negotiation period — Preliminary work
proved by Uruguay — Breach by Uruguay of the obligation to negotiate laid
wn by Article 12 of the 1975 Statute.

                                                                             9

Obligations of Uruguay following the end of the negotiation period — Scope
Article 12 of the 1975 Statute — Absence of a “no construction obligation”
lowing the end of the negotiation period and during the judicial settlement
ase.

                                      *
Alleged breaches of substantive obligations.
Burden of proof — Precautionary approach without reversal of the burden of
oof — Expert evidence — Reports commissioned by the Parties — Independ-
ce of experts — Consideration of the facts by the Court — Experts appearing
 counsel at the hearings — Question of witnesses, experts and expert wit-
 ses.
Optimum and rational utilization of the River Uruguay — Article 1 of the
75 Statute sets out the purpose of the instrument and does not lay down
 cific rights and obligations — Obligation to comply with the obligations
 scribed by the Statute for the protection of the environment and the joint
 nagement of the river — Regulatory function of CARU — Interconnected-
 s between equitable and reasonable utilization of the river as a shared
 ource and the balance between economic development and environmental
otection that is the essence of sustainable development (Article 27 of the 1975
atute).
Obligation to ensure that the management of the soil and woodland does not
pair the régime of the river or the quality of its waters (Article 35 of the 1975
atute) — Contentions of Argentina not established.
Obligation to co-ordinate measures to avoid changes to the ecological balance
 rticle 36 of the 1975 Statute) — Requirement of individual action by each
rty and co-ordination through CARU — Obligation of due diligence —
gentina has not convincingly demonstrated that Uruguay has refused to
gage in the co-ordination envisaged by Article 36 of the 1975 Statute.

Obligation to prevent pollution and preserve the aquatic environment — Norm-
ve content of Article 41 of the 1975 Statute — Obligation for each party to
opt rules and measures to protect and preserve the aquatic environment and,
particular, to prevent pollution — The rules and measures prescribed by each
rty must be in accordance with applicable international agreements and in
eping, where relevant, with the guidelines and recommendations of interna-
nal technical bodies — Due diligence obligation to prescribe rules and meas-
 s and to apply them — Definition of pollution given in Article 40 of the
75 Statute — Regulatory action of CARU (Article 56 of the 1975 Statute),
mplementing that of each party — CARU Digest — Rules by which the exist-
ce of any harmful effects is to be determined : 1975 Statute, CARU Digest,
mestic law of each party within the limits prescribed by the 1975 Statute.

Environmental impact assessment (EIA) — Obligation to conduct an EIA —
ope and content of the EIA — Referral to domestic law — Question of the
oice of mill site as part of the EIA — The Court is not convinced by Argen-
a’s argument that an assessment of possible sites was not carried out —
ceiving capacity of the river at Fray Bentos and reverse flows — The CARU
ter quality standards take account of the geomorphological and hydrological
aracteristics of the river and the receiving capacity of its waters — Question

                                                                              10

 consultation of the affected populations as part of the EIA — No legal obli-
tion to consult the affected populations arises from the instruments invoked
 Argentina — Consultation by Uruguay of the affected populations did indeed
ke place.

Production technology used in the Orion (Botnia) mill — No evidence to sup-
rt Argentina’s claim that the Orion (Botnia) mill is not BAT-compliant in
 ms of the discharges of effluent for each tonne of pulp produced — From the
ta collected after the start-up of the Orion (Botnia) mill, it does not appear
at the discharges from it have exceeded the prescribed limits.

Impact of the discharges on the quality of the waters of the river — Post-
erational monitoring — Dissolved oxygen — Phosphorus — Algal blooms —
 enolic substances — Presence of nonylphenols in the river environment —
oxins and furans — Alleged breaches not established.
Effects on biodiversity — Insufficient evidence to conclude that Uruguay
 ached the obligation to protect the aquatic environment, including its fauna
d flora.
Air pollution — Indirect pollution from deposits into the aquatic environ-
 nt — Insufficient evidence.
On the basis of the evidence submitted, no breach by Uruguay of Article 41 of
  1975 Statute.
Continuing obligations : monitoring — Obligation of the Parties to enable
ARU to exercise on a continuous basis the powers conferred on it by the
75 Statute — Obligation of Uruguay to continue monitoring the operation of
  Orion (Botnia) plant — Obligation of the Parties to continue their co-op-
 tion through CARU.

                                     *
Claims made by the Parties in their final submissions.
Claims of Argentina — Breach of procedural obligations — Finding of
ongful conduct and satisfaction — Forms of reparation other than compensa-
n not excluded by the 1975 Statute — Restitution as a form of reparation
  injury — Definition — Limits — Form of reparation appropriate to the
ury suffered, taking into account the nature of the wrongful act — Restitution
the form of the dismantling of the Orion (Botnia) mill not appropriate
ere only breaches of procedural obligations have occurred — No breach
 substantive obligations and rejection of Argentina’s other claims — No
 cial circumstances requiring the ordering of assurances and guarantees
non-repetition.

Uruguay’s request for confirmation of its right to continue operating the
ion (Botnia) plant — No practical significance.

                                     *
Obligation of the Parties to co-operate with each other, on the terms set out
the 1975 Statute, to ensure the achievement of its object and purpose — Joint
 ion of the Parties through CARU and establishment of a real community of
erests and rights in the management of the River Uruguay and in the protec-
n of its environment.

                                                                           11

                             JUDGMENT

esent : Vice-President TOMKA, Acting President ; Judges KOROMA,
        AL-KHASAWNEH, SIMMA, ABRAHAM, KEITH, SEPÚLVEDA-AMOR,
        BENNOUNA, SKOTNIKOV, CANÇADO TRINDADE, YUSUF, GREENWOOD ;
        Judges ad hoc TORRES BERNÁRDEZ, VINUESA ; Registrar COUVREUR.

In the case concerning pulp mills on the River Uruguay,
between
  Argentine Republic,
presented by
H.E. Ms Susana Ruiz Cerutti, Ambassador, Legal Adviser to the Ministry of
   Foreign Affairs, International Trade and Worship,
as Agent ;
H.E. Mr. Horacio A. Basabe, Ambassador, Director of the Argentine Insti-
   tute for Foreign Service, former Legal Adviser to the Ministry of Foreign
   Affairs, International Trade and Worship, Member of the Permanent
   Court of Arbitration,
H.E. Mr. Santos Goñi Marenco, Ambassador of the Argentine Republic to
   the Kingdom of the Netherlands,
as Co-Agents ;
Mr. Alain Pellet, Professor at the University of Paris Ouest, Nanterre-
   La Défense, member and former Chairman of the International Law Com-
   mission, associate member of the Institut de droit international,
Mr. Philippe Sands, Q.C., Professor of International Law at University Col-
   lege London, Barrister at Matrix Chambers, London,
Mr. Marcelo Kohen, Professor of International Law at the Graduate Insti-
   tute of International and Development Studies, Geneva, associate member
   of the Institut de droit international,
Ms Laurence Boisson de Chazournes, Professor of International Law at the
   University of Geneva,
Mr. Alan Béraud, Minister at the Embassy of the Argentine Republic to the
   European Union, former Legal Adviser to the Ministry of Foreign Affairs,
   International Trade and Worship,
Mr. Daniel Müller, Researcher at the Centre de droit international de
   Nanterre (CEDIN), University of Paris Ouest, Nanterre-La Défense,
as Counsel and Advocates ;
Mr. Homero Bibiloni, Federal Secretary for the Environment and Sustain-
   able Development,
as Governmental Authority ;
Mr. Esteban Lyons, National Director of Environmental Control, Secre-
   tariat of the Environment and Sustainable Development,
Mr. Howard Wheater, Ph.D. in Hydrology from Bristol University, Profes-
   sor of Hydrology at Imperial College and Director of the Imperial College
   Environment Forum,

                                                                         12

Mr. Juan Carlos Colombo, Ph.D. in Oceanography from the University of
 Quebec, Professor at the Faculty of Sciences and Museum of the National
 University of La Plata, Director of the Laboratory of Environmental
 Chemistry and Biogeochemistry at the National University of La Plata,
Mr. Neil McIntyre, Ph.D. in Environmental Engineering, Senior Lecturer in
 Hydrology at Imperial College London,
Ms Inés Camilloni, Ph.D. in Atmospheric Sciences, Professor of Atmos-
 pheric Sciences in the Faculty of Sciences of the University of Buenos
 Aires, Senior Researcher at the National Research Council (CONICET),

Mr. Gabriel Raggio, Doctor in Technical Sciences of the Swiss Federal Insti-
 tute of Technology Zurich (ETHZ) (Switzerland), Independent Consult-
 ant,
as Scientific Advisers and Experts ;
Mr. Holger Martinsen, Minister at the Office of the Legal Adviser, Ministry
 of Foreign Affairs, International Trade and Worship,
Mr. Mario Oyarzábal, Embassy Counsellor, member of the Office of the
 Legal Adviser, Ministry of Foreign Affairs, International Trade and Wor-
 ship,
Mr. Fernando Marani, Second Secretary, Embassy of the Argentine Repub-
 lic in the Kingdom of the Netherlands,
Mr. Gabriel Herrera, Embassy Secretary, member of the Office of the Legal
 Adviser, Ministry of Foreign Affairs, International Trade and Worship,

Ms Cynthia Mulville, Embassy Secretary, member of the Office of the Legal
 Adviser, Ministry of Foreign Affairs, International Trade and Worship,

Ms Kate Cook, Barrister at Matrix Chambers, London, specializing in environ-
 mental law and law relating to development,
Ms Mara Tignino, Ph.D. in Law, Researcher at the University of Geneva,
Mr. Magnus Jesko Langer, teaching and research assistant, Graduate Insti-
 tute of International and Development Studies, Geneva,
as Legal Advisers,

and

 Eastern Republic of Uruguay,
presented by
H.E. Mr. Carlos Gianelli, Ambassador of the Eastern Republic of Uruguay
  to the United States of America,
as Agent ;
H.E. Mr. Carlos Mora Medero, Ambassador of the Eastern Republic of
  Uruguay to the Kingdom of the Netherlands,
as Co-Agent ;
Mr. Alan Boyle, Professor of International Law at the University of Edin-
 burgh, Member of the English Bar,
Mr. Luigi Condorelli, Professor at the Faculty of Law, University of Flor-
 ence,

                                                                         13

Mr. Lawrence H. Martin, Foley Hoag LLP, Member of the Bars of the
 United States Supreme Court, the District of Columbia and the Common-
 wealth of Massachusetts,
Mr. Stephen C. McCaffrey, Professor at the McGeorge School of Law, Uni-
 versity of the Pacific, California, former Chairman of the International
 Law Commission and Special Rapporteur for the Commission’s work on
 the law of non-navigational uses of international watercourses,

Mr. Alberto Pérez Pérez, Professor in the Faculty of Law, University of the
 Republic, Montevideo,
Mr. Paul S. Reichler, Foley Hoag LLP, Member of the Bars of the United
 States Supreme Court and the District of Columbia,

as Counsel and Advocates ;
Mr. Marcelo Cousillas, Legal Counsel at the National Directorate for the
 Environment, Ministry of Housing, Land Use Planning and Environmen-
 tal Affairs,
Mr. César Rodriguez Zavalla, Chief of Cabinet, Ministry of Foreign Affairs,

Mr. Carlos Mata, Deputy Director of Legal Affairs, Ministry of Foreign
 Affairs,
Mr. Marcelo Gerona, Counsellor at the Embassy of the Eastern Republic of
 Uruguay in the Kingdom of the Netherlands,
Mr. Eduardo Jiménez de Aréchaga, Attorney at Law, admitted to the Bar of
 the Eastern Republic of Uruguay and Member of the Bar of New York,
Mr. Adam Kahn, Foley Hoag LLP, Member of the Bar of the Common-
 wealth of Massachusetts,
Mr. Andrew Loewenstein, Foley Hoag LLP, Member of the Bar of the Com-
 monwealth of Massachusetts,
Ms Analia Gonzalez, LL.M., Foley Hoag LLP, admitted to the Bar of the
 Eastern Republic of Uruguay,
Ms Clara E. Brillembourg, Foley Hoag LLP, Member of the Bars of the Dis-
 trict of Columbia and New York,
Ms Cicely Parseghian, Foley Hoag LLP, Member of the Bar of the Com-
 monwealth of Massachusetts,
Mr. Pierre Harcourt, Ph.D. candidate, University of Edinburgh,
Mr. Paolo Palchetti, Associate Professor at the School of Law, University of
 Macerata,
Ms Maria E. Milanes-Murcia, M.A., LL.M., J.S.D. Candidate at the
 McGeorge School of Law, University of the Pacific, California, Ph.D.
 Candidate, University of Murcia, admitted to the Bar of Spain,
as Assistant Counsel ;
Ms Alicia Torres, National Director for the Environment at the Ministry of
 Housing, Land Use Planning and Environmental Affairs,
Mr. Eugenio Lorenzo, Technical Consultant for the National Directorate for
 the Environment, Ministry of Housing, Land Use Planning and Environ-
 mental Affairs,
Mr. Cyro Croce, Technical Consultant for the National Directorate for the
 Environment, Ministry of Housing, Land Use Planning and Environmen-
 tal Affairs,

                                                                         14

Ms Raquel Piaggio, State Agency for Sanitary Works (OSE), Technical Con-
 sultant for the National Directorate for the Environment, Ministry of
 Housing, Land Use Planning and Environmental Affairs,

Mr. Charles A. Menzie, Ph.D., Principal Scientist and Director of the Eco-
  Sciences Practice at Exponent, Inc., Alexandria, Virginia,
Mr. Neil McCubbin, Eng., B.Sc. (Eng.), 1st Class Honours, Glasgow, Asso-
  ciate of the Royal College of Science and Technology, Glasgow,
as Scientific Advisers and Experts,

THE COURT,
composed as above,
after deliberation,
delivers the following Judgment :
1. On 4 May 2006, the Argentine Republic (hereinafter “Argentina”) filed in
   Registry of the Court an Application instituting proceedings against the
 stern Republic of Uruguay (hereinafter “Uruguay”) in respect of a dispute
ncerning the breach, allegedly committed by Uruguay, of obligations under
   Statute of the River Uruguay (United Nations, Treaty Series (UNTS),
 l. 1295, No. I-21425, p. 340), a treaty signed by Argentina and Uruguay at
  to (Uruguay) on 26 February 1975 and having entered into force on 18 Sep-
mber 1976 (hereinafter the “1975 Statute”) ; in the Application, Argentina
 ted that this breach arose out of “the authorization, construction and future
mmissioning of two pulp mills on the River Uruguay”, with reference in par-
ular to “the effects of such activities on the quality of the waters of the River
 uguay and on the areas affected by the river”.
In its Application, Argentina, referring to Article 36, paragraph 1, of the
atute of the Court, seeks to found the jurisdiction of the Court on Article 60,
ragraph 1, of the 1975 Statute.
2. Pursuant to Article 40, paragraph 2, of the Statute of the Court, the Reg-
rar communicated the Application forthwith to the Government of Uruguay.
  accordance with paragraph 3 of that Article, the Secretary-General of the
nited Nations was notified of the filing of the Application.
3. On 4 May 2006, immediately after the filing of the Application, Argentina
 o submitted a request for the indication of provisional measures based on
 ticle 41 of the Statute and Article 73 of the Rules of Court. In accordance
  h Article 73, paragraph 2, of the Rules of Court, the Registrar transmitted a
 tified copy of this request forthwith to the Government of Uruguay.

4. On 2 June 2006, Uruguay transmitted to the Court a CD-ROM contain-
  the electronic version of two volumes of documents relating to the Argen-
e request for the indication of provisional measures, entitled “Observations
 Uruguay” (of which paper copies were subsequently received) ; a copy of
 se documents was immediately sent to Argentina.
5. On 2 June 2006, Argentina transmitted to the Court various docu-
 nts, including a video recording, and, on 6 June 2006, it transmitted further
cuments ; copies of each series of documents were immediately sent to Uru-
ay.
6. On 6 and 7 June 2006, various communications were received from the

                                                                              15

 rties, whereby each Party presented the Court with certain observations on
   documents submitted by the other Party. Uruguay objected to the produc-
 n of the video recording submitted by Argentina. The Court decided not to
 thorize the production of that recording at the hearings.
 7. Since the Court included upon the Bench no judge of the nationality of
   Parties, each of them exercised its right under Article 31, paragraph 3, of
    Statute to choose a judge ad hoc to sit in the case. Argentina chose
 r. Raúl Emilio Vinuesa, and Uruguay chose Mr. Santiago Torres Bernárdez.

 8. By an Order of 13 July 2006, the Court, having heard the Parties, found
hat the circumstances, as they [then] present[ed] themselves to [it], [we]re not
ch as to require the exercise of its power under Article 41 of the Statute to
dicate provisional measures”.
 9. By another Order of the same date, the Court, taking account of the views
 the Parties, fixed 15 January 2007 and 20 July 2007, respectively, as the time-
mits for the filing of a Memorial by Argentina and a Counter-Memorial by
 uguay ; those pleadings were duly filed within the time-limits so prescribed.

10. On 29 November 2006, Uruguay, invoking Article 41 of the Statute and
 ticle 73 of the Rules of Court, in turn submitted a request for the indication
  provisional measures. In accordance with Article 73, paragraph 2, of the
  les of Court, the Registrar transmitted a certified copy of this request forth-
  h to the Argentine Government.
11. On 14 December 2006, Uruguay transmitted to the Court a volume of
 cuments concerning the request for the indication of provisional measures,
  itled “Observations of Uruguay” ; a copy of these documents was immedi-
  ly sent to Argentina.
12. On 18 December 2006, before the opening of the oral proceedings,
 gentina transmitted to the Court a volume of documents concerning Uru-
ay’s request for the indication of provisional measures ; the Registrar imme-
  tely sent a copy of these documents to the Government of Uruguay.
13. By an Order of 23 January 2007, the Court, having heard the Parties,
und “that the circumstances, as they [then] present[ed] themselves to [it],
e]re not such as to require the exercise of its power under Article 41 of the
atute to indicate provisional measures”.
14. By an Order of 14 September 2007, the Court, taking account of the
reement of the Parties and of the circumstances of the case, authorized the
bmission of a Reply by Argentina and a Rejoinder by Uruguay, and fixed
  January 2008 and 29 July 2008 as the respective time-limits for the filing of
ose pleadings. The Reply of Argentina and the Rejoinder of Uruguay were
 ly filed within the time-limits so prescribed.
15. By letters dated 16 June 2009 and 17 June 2009 respectively, the Gov-
nments of Uruguay and Argentina notified the Court that they had come to
   agreement for the purpose of producing new documents pursuant to Arti-
   56 of the Rules of Court. By letters of 23 June 2009, the Registrar informed
   Parties that the Court had decided to authorize them to proceed as they had
reed. The new documents were duly filed within the agreed time-limit.

 16. On 15 July 2009, each of the Parties, as provided for in the agreement
  ween them and with the authorization of the Court, submitted comments on
   new documents produced by the other Party. Each Party also filed docu-
  nts in support of these comments.

                                                                              16

17. In accordance with Article 53, paragraph 2, of the Rules of Court, the
 urt decided, after ascertaining the views of the Parties, that copies of the
 adings and documents annexed would be made available to the public as
 m the opening of the oral proceedings.
18. By letter of 15 September 2009, Uruguay, referring to Article 56, para-
aph 4, of the Rules of Court and to Practice Direction IXbis, communicated
cuments to the Court, forming part of publications readily available, on
 ich it intended to rely during the oral proceedings. Argentina made no objec-
 n with regard to these documents.
19. By letter of 25 September 2009, the Argentine Government, referring to
 ticle 56 of the Rules of Court and to Practice Direction IX, paragraph 2, sent
w documents to the Registry which it wished to produce. By letter of 28 Sep-
mber 2009, the Government of Uruguay informed the Court that it was
posed to the production of these documents. It further indicated that if,
vertheless, the Court decided to admit the documents in question into the
 ord of the case, it would present comments on them and submit documents
 support of those comments. By letters dated 28 September 2009, the Regis-
 r informed the Parties that the Court did not consider the production of the
w documents submitted by the Argentine Government to be necessary within
   meaning of Article 56, paragraph 2, of the Rules of Court, and that it had
t moreover identified any exceptional circumstance (Practice Direction IX,
ragraph 3) which justified their production at that stage of the proceedings.

20. Public hearings were held between 14 September 2009 and 2 October
09, at which the Court heard the oral arguments and replies of :

r Argentina : H.E. Ms Susana Ruiz Cerutti,
              Mr. Alain Pellet,
              Mr. Philippe Sands,
              Mr. Howard Wheater,
              Ms Laurence Boisson de Chazournes,
              Mr. Marcelo Kohen,
              Mr. Alan Béraud,
              Mr. Juan Carlos Colombo,
              Mr. Daniel Müller.
r Uruguay :    H.E. Mr. Carlos Gianelli,
               Mr. Alan Boyle,
               Mr. Paul S. Reichler,
               Mr. Neil McCubbin,
               Mr. Stephen C. McCaffrey,
               Mr. Lawrence H. Martin,
               Mr. Luigi Condorelli.
21. At the hearings, Members of the Court put questions to the Parties,
 which replies were given orally and in writing, in accordance with Arti-
  61, paragraph 4, of the Rules of Court. Pursuant to Article 72 of the
ules of Court, one of the Parties submitted written comments on a written
ply provided by the other and received after the closure of the oral pro-
edings.

                                     *
                                                                            17

22. In its Application, the following claims were made by Argentina :
    “On the basis of the foregoing statement of facts and law, Argentina,
  while reserving the right to supplement, amend or modify the present
  Application in the course of the subsequent procedure, requests the Court
  to adjudge and declare :
  1. that Uruguay has breached the obligations incumbent upon it under
     the 1975 Statute and the other rules of international law to which that
     instrument refers, including but not limited to :
     (a) the obligation to take all necessary measures for the optimum and
          rational utilization of the River Uruguay ;
     (b) the obligation of prior notification to CARU and to Argentina ;
     (c) the obligation to comply with the procedures prescribed in Chap-
          ter II of the 1975 Statute ;
     (d) the obligation to take all necessary measures to preserve the
          aquatic environment and prevent pollution and the obligation to
          protect biodiversity and fisheries, including the obligation to pre-
          pare a full and objective environmental impact study ;

     (e) the obligation to co-operate in the prevention of pollution and the
           protection of biodiversity and of fisheries ; and
  2. that, by its conduct, Uruguay has engaged its international responsibil-
     ity to Argentina ;
  3. that Uruguay shall cease its wrongful conduct and comply scrupulously
     in future with the obligations incumbent upon it ; and
  4. that Uruguay shall make full reparation for the injury caused by its
     breach of the obligations incumbent upon it.
    Argentina reserves the right to amplify or amend these requests at a sub-
  sequent stage of the proceedings.”
23. In the written proceedings, the following submissions were presented by
 Parties :
 behalf of the Government of Argentina,
the Memorial :
    “For all the reasons described in this Memorial, the Argentine Republic
  requests the International Court of Justice :

  1. to find that by unilaterally authorizing the construction of the CMB
     and Orion pulp mills and the facilities associated with the latter on the
     left bank of the River Uruguay, in breach of the obligations resulting
     from the Statute of 26 February 1975, the Eastern Republic of
     Uruguay has committed the internationally wrongful acts set out in
     Chapters IV and V of this Memorial, which entail its international
     responsibility ;
  2. to adjudge and declare that, as a result, the Eastern Republic of Uruguay
     must :
       (i) cease immediately the internationally wrongful acts referred to
           above ;
      (ii) resume strict compliance with its obligations under the Statute of
           the River Uruguay of 1975 ;

                                                                           18

      (iii) re-establish on the ground and in legal terms the situation that
            existed before the internationally wrongful acts referred to above
            were committed ;
      (iv) pay compensation to the Argentine Republic for the damage
            caused by these internationally wrongful acts that would not be
            remedied by that situation being restored, of an amount to be
            determined by the Court at a subsequent stage of these proceed-
            ings ;
       (v) provide adequate guarantees that it will refrain in future from pre-
            venting the Statute of the River Uruguay of 1975 from being
            applied, in particular the consultation procedure established by
            Chapter II of that Treaty.
     The Argentine Republic reserves the right to supplement or amend these
  submissions should the need arise, in the light of the development of the
  situation. This would in particular apply if Uruguay were to aggravate
  the dispute1, for example if the Orion mill were to be commissioned before
  the end of these proceedings.

     1
       See the Order of the Court of 13 July 2006 on Argentina’s request for the indica-
  tion of provisional measures, para. 82.”

the Reply :
     “For all the reasons described in its Memorial, which it fully stands by,
  and in the present Reply, the Argentine Republic requests the Interna-
  tional Court of Justice :
  1. to find that by authorizing
      — the construction of the CMB mill ;
      — the construction and commissioning of the Orion mill and its asso-
           ciated facilities on the left bank of the River Uruguay,
      the Eastern Republic of Uruguay has violated the obligations incum-
      bent on it under the Statute of the River Uruguay of 26 February 1975
      and has engaged its international responsibility ;
  2. to adjudge and declare that, as a result, the Eastern Republic of Uru-
      guay must :
        (i) resume strict compliance with its obligations under the Statute of
            the River Uruguay of 1975 ;
       (ii) cease immediately the internationally wrongful acts by which it
            has engaged its responsibility ;
      (iii) re-establish on the ground and in legal terms the situation that
            existed before these internationally wrongful acts were committed ;
      (iv) pay compensation to the Argentine Republic for the damage
            caused by these internationally wrongful acts that would not be
            remedied by that situation being restored, of an amount to be
            determined by the Court at a subsequent stage of these proceed-
            ings ;
       (v) provide adequate guarantees that it will refrain in future from pre-
            venting the Statute of the River Uruguay of 1975 from being
            applied, in particular the consultation procedure established by
            Chapter II of that Treaty.

                                                                                19

     The Argentine Republic reserves the right to supplement or amend these
  submissions should the need arise, in the light of subsequent developments
  in the case.”
 behalf of the Government of Uruguay,
the Counter-Memorial :
     “On the basis of the facts and arguments set out above, and reserving its
  right to supplement or amend these Submissions, Uruguay requests that
  the Court adjudge and declare that the claims of Argentina are rejected.”
the Rejoinder :
    “Based on all the above, it can be concluded that :
  (a) Argentina has not demonstrated any harm, or risk of harm, to the
      river or its ecosystem resulting from Uruguay’s alleged violations of
      its substantive obligations under the 1975 Statute that would be suf-
      ficient to warrant the dismantling of the Botnia plant ;

  (b) the harm to the Uruguayan economy in terms of lost jobs and rev-
       enue would be substantial ;
  (c) in light of points (a) and (b), the remedy of tearing the plant down
      would therefore be disproportionately onerous, and should not be
      granted ;
  (d) if the Court finds, notwithstanding all the evidence to the contrary,
       that Uruguay has violated its procedural obligations to Argentina, it
       can issue a declaratory judgment to that effect, which would consti-
       tute an adequate form of satisfaction ;
  (e) if the Court finds, notwithstanding all the evidence to the contrary,
      that the plant is not in complete compliance with Uruguay’s obliga-
      tion to protect the river or its aquatic environment, the Court can
      order Uruguay to take whatever additional protective measures are
      necessary to ensure that the plant conforms to the Statute’s substan-
      tive requirements ;
  (f) if the Court finds, notwithstanding all the evidence to the contrary,
      that Uruguay has actually caused damage to the river or to Argen-
      tina, it can order Uruguay to pay Argentina monetary compensation
      under Articles 42 and 43 of the Statute ; and
  (g) the Court should issue a declaration making clear the Parties are obli-
       gated to ensure full respect for all the rights in dispute in this case,
       including Uruguay’s right to continue operating the Botnia plant in
       conformity with the provisions of the 1975 Statute.

                                  Submissions
     On the basis of the facts and arguments set out above, and reserving its
  right to supplement or amend these Submissions, Uruguay requests that
  the Court adjudge and declare that the claims of Argentina are rejected,
  and Uruguay’s right to continue operating the Botnia plant in conformity
  with the provisions of the 1975 Statute is affirmed.”
24. At the oral proceedings, the following final submissions were presented
 the Parties :

                                                                            20

 behalf of the Government of Argentina,
the hearing of 29 September 2009 :
    “For all the reasons described in its Memorial, in its Reply and in the
  oral proceedings, which it fully stands by, the Argentine Republic requests
  the International Court of Justice :

  1. to find that by authorizing
     — the construction of the ENCE mill ;
     — the construction and commissioning of the Botnia mill and its asso-
          ciated facilities on the left bank of the River Uruguay,
     the Eastern Republic of Uruguay has violated the obligations incum-
     bent on it under the Statute of the River Uruguay of 26 February 1975
     and has engaged its international responsibility ;
  2. to adjudge and declare that, as a result, the Eastern Republic of Uru-
     guay must :
       (i) resume strict compliance with its obligations under the Statute of
           the River Uruguay of 1975 ;
      (ii) cease immediately the internationally wrongful acts by which it
           has engaged its responsibility ;
     (iii) re-establish on the ground and in legal terms the situation that
           existed before these internationally wrongful acts were committed ;
     (iv) pay compensation to the Argentine Republic for the damage
           caused by these internationally wrongful acts that would not be
           remedied by that situation being restored, of an amount to be
           determined by the Court at a subsequent stage of these proceed-
           ings ;
      (v) provide adequate guarantees that it will refrain in future from pre-
           venting the Statute of the River Uruguay of 1975 from being
           applied, in particular the consultation procedure established by
           Chapter II of that Treaty.”
 behalf of the Government of Uruguay,
the hearing of 2 October 2009 :
     “On the basis of the facts and arguments set out in Uruguay’s Counter-
  Memorial, Rejoinder and during the oral proceedings, Uruguay requests
  that the Court adjudge and declare that the claims of Argentina are
  rejected, and Uruguay’s right to continue operating the Botnia plant in
  conformity with the provisions of the 1975 Statute is affirmed.”

                                  * * *

                         I. LEGAL FRAMEWORK
                        AND FACTS OF THE CASE

. The dispute before the Court has arisen in connection with the
anned construction authorized by Uruguay of one pulp mill and the
nstruction and commissioning of another, also authorized by Uruguay,

                                                                           21

  the River Uruguay (see sketch-map No. 1 on p. 33 for the general
ographical context). After identifying the legal instruments concerning
e River Uruguay by which the Parties are bound, the Court will set out
e main facts of the case.

                         A. Legal Framework
26. The boundary between Argentina and Uruguay in the River Uru-
ay is defined by the bilateral Treaty entered into for that purpose at
ontevideo on 7 April 1961 (UNTS, Vol. 635, No. 9074, p. 98). Arti-
 s 1 to 4 of the Treaty delimit the boundary between the Contracting
ates in the river and attribute certain islands and islets in it to them.
 ticles 5 and 6 concern the régime for navigation on the river. Article 7
ovides for the establishment by the parties of a “régime for the use of
e river” covering various subjects, including the conservation of living
 ources and the prevention of water pollution of the river. Articles 8 to
  lay down certain obligations concerning the islands and islets and
eir inhabitants.
27. The “régime for the use of the river” contemplated in Article 7 of
e 1961 Treaty was established through the 1975 Statute (see para-
aph 1 above). Article 1 of the 1975 Statute states that the parties
opted it “in order to establish the joint machinery necessary for the
 timum and rational utilization of the River Uruguay, in strict observ-
ce of the rights and obligations arising from treaties and other inter-
tional agreements in force for each of the parties”. After having thus
fined its purpose (Article 1) and having also made clear the meaning of
rtain terms used therein (Article 2), the 1975 Statute lays down rules
verning navigation and works on the river (Chapter II, Articles 3 to
), pilotage (Chapter III, Articles 14 to 16), port facilities, unloading
d additional loading (Chapter IV, Articles 17 to 18), the safeguarding
 human life (Chapter V, Articles 19 to 23) and the salvaging of property
hapter VI, Articles 24 to 26), use of the waters of the river (Chap-
  VII, Articles 27 to 29), resources of the bed and subsoil (Chapter VIII,
 ticles 30 to 34), the conservation, utilization and development of other
tural resources (Chapter IX, Articles 35 to 39), pollution (Chapter X,
 ticles 40 to 43), scientific research (Chapter XI, Articles 44 to 45), and
rious powers of the parties over the river and vessels sailing on it
hapter XII, Articles 46 to 48). The 1975 Statute sets up the Adminis-
 tive Commission of the River Uruguay (hereinafter “CARU”, from
e Spanish acronym for “Comisión Administradora del Río Uruguay”)
hapter XIII, Articles 49 to 57), and then establishes procedures for
nciliation (Chapter XIV, Articles 58 to 59) and judicial settlement of
 putes (Chapter XV, Article 60). Lastly, the 1975 Statute contains tran-
ional (Chapter XVI, Articles 61 to 62) and final (Chapter XVII, Arti-
  63) provisions.

                                                                        22

                                                                      Sketch-map No. 1:
                                                                 General geographical context
                                                                         Mercator Projection
                                                                                (33°30' S)
               River Guale

                                                                                WGS 84
                                                                     This sketch-map has been prepared
                                                                        for illustrative purposes only.
                           guaychú

Gualeguaychú

                                      Fray Bentos
                                      (location of Orion (Botnia) mill)
ARGENTINA

        River Uruguay

                                                                    URUGUAY
                                     Nueva Palmira

 BUENOS AIRES                                        Río
                                                         de
                                                            la
                                                                 Pla
                                                                    ta                                    MONTEVIDEO

                                                                                23

                      B. CMB (ENCE) Project

 28. The first pulp mill at the root of the dispute was planned by “Celu-
  as de M’Bopicuá S.A.” (hereinafter “CMB”), a company formed by
e Spanish company ENCE (from the Spanish acronym for “Empresa
acional de Celulosas de España”, hereinafter “ENCE”). This mill, here-
after referred to as the “CMB (ENCE)” mill, was to have been built on
e left bank of the River Uruguay in the Uruguayan department of Río
egro opposite the Argentine region of Gualeguaychú, more specifically
  the east of the city of Fray Bentos, near the “General San Martín”
  ernational bridge (see sketch-map No. 2 on p. 35).
 29. On 22 July 2002, the promoters of this industrial project
 proached the Uruguayan authorities and submitted an environ-
ental impact assessment (“EIA” according to the abbreviation used by
e Parties) of the plan to Uruguay’s National Directorate for the
  vironment (hereinafter “DINAMA”, from the Spanish acronym for
Dirección Nacional de Medio Ambiente”). During the same period, rep-
  entatives of CMB, which had been specially formed to build the CMB
 NCE) mill, informed the President of CARU of the project. The Presi-
 nt of CARU wrote to the Uruguayan Minister of the Environment on
  October 2002 seeking a copy of the environmental impact assessment
  the CMB (ENCE) project submitted by the promoters of this indus-
 al project. This request was reiterated on 21 April 2003. On
  May 2003, Uruguay submitted to CARU a document entitled “Envi-
 nmental Impact Study, Celulosas de M’Bopicuá. Summary for public
 ease”. One month later, the CARU Subcommittee on Water Quality
 d Pollution Control took notice of the document transmitted by
  uguay and suggested that a copy thereof be sent to its technical
 visers for their opinions. Copies were also provided to the Parties’
 legations.

30. A public hearing, attended by CARU’s Legal Adviser and its tech-
cal secretary, was held on 21 July 2003 in the city of Fray Bentos con-
rning CMB’s application for an environmental authorization. On
  August 2003, CARU asked Uruguay for further information on vari-
 s points concerning the planned CMB (ENCE) mill. This request was
 terated on 12 September 2003. On 2 October 2003, DINAMA submit-
d its assessment report to the Uruguayan Ministry of Housing, Land
 e Planning and Environmental Affairs (hereinafter “MVOTMA”, from
e Spanish abbreviation for “Ministerio de Vivienda Ordenamiento Ter-
orial y Medio Ambiente”), recommending that CMB be granted an ini-
 l environmental authorization (“AAP” according to the Spanish abbre-
ation for “Autorización Ambiental Previa”) subject to certain condi-
 ns. On 8 October 2003, CARU was informed by the Uruguayan
legation that DINAMA would very shortly send CARU a report on
e CMB (ENCE) project.

                                                                      24

     Gualeguaychú
                                                                        ARGENTINA

                    River
                          Guale
                                guayc
                                     hú
                                                                                Inés Lagoon

                                                   Ñandubaysal Bay

                                                                                Martín
                                                                                l San
                                                                                Generabridge
                                                                                CMB (ENCE) mill (planned but not built)
                                                                                Orion (Botnia) mill
                                                                            Fray Bentos

               Sketch-map No. 2:
      Siting of the Orion (Botnia) mill and
     the planned CMB (ENCE) mill (not built)

                Mercator Projection                                                                                URUGUAY

                                                                   ay
                                          (33°S)

                                                                ugu
                                      WGS84

                                                            r Ur
                                                       Rive
            This sketch-map has been prepared
               for illustrative purposes only.

25

31. On 9 October 2003, MVOTMA issued an initial environmental
 thorization to CMB for the construction of the CMB (ENCE) mill. On
e same date the Presidents of Argentina and Uruguay met at Anchorena
olonia, Uruguay). Argentina maintains that the President of Uruguay,
rge Battle, then promised his Argentine counterpart, Néstor Kirchner,
at no authorization would be issued before Argentina’s environmental
ncerns had been addressed. Uruguay challenges this version of the
cts and contends that the Parties agreed at that meeting to deal with the
MB (ENCE) project otherwise than through the procedure under Arti-
 s 7 to 12 of the 1975 Statute and that Argentina let it be known that it
  s not opposed to the project per se. Argentina disputes these assertions.

 32. The day after the meeting between the Heads of State of Argentina
 d Uruguay, CARU declared its willingness to resume the technical
 alyses of the CMB (ENCE) project as soon as Uruguay transmitted the
 aited documents. On 17 October 2003, CARU held an extraordinary
enary meeting at the request of Argentina, at which Argentina
mplained of Uruguay’s granting on 9 October 2003 of the initial envi-
nmental authorization. Following the extraordinary meeting CARU
spended work for more than six months, as the Parties could not agree
  how to implement the consultation mechanism established by the
 75 Statute.
 33. On 27 October 2003, Uruguay transmitted to Argentina copies of
e environmental impact assessment submitted by ENCE on 22 July
 02, of DINAMA’s final assessment report dated 2 October 2003 and of
e initial environmental authorization of 9 October 2003. Argentina
acted by expressing its view that Article 7 of the 1975 Statute had not
en observed and that the transmitted documents did not appear
 equate to allow for a technical opinion to be expressed on the environ-
ental impact of the project. On 7 November 2003, further to a request
om the Ministry of Foreign Affairs of Argentina, Uruguay provided
 gentina with a copy of the Uruguayan Ministry of the Environment’s
tire file on the CMB (ENCE) project. On 23 February 2004, Argentina
rwarded all of this documentation received from Uruguay to CARU.

34. On 2 March 2004, the Parties’ Ministers for Foreign Affairs met in
 enos Aires. On 15 May 2004, CARU resumed its work at an extra-
dinary plenary meeting during which it took note of the ministerial
nderstanding” which was reached on 2 March 2004. The Parties are at
ds over the content of this “understanding”. The Court will return to
s when it considers Argentina’s claims as to Uruguay’s breach of its
ocedural obligations under the 1975 Statute (see paragraphs 67 to 158).

35. Following up on CARU’s extraordinary meeting of 15 May 2004,
e CARU Subcommittee on Water Quality and Pollution Control pre-

                                                                        26

red a plan for monitoring water quality in the area of the pulp mills
ereinafter the “PROCEL” plan from the Spanish acronym for “Plan de
onitoreo de la Calidad Ambiental del Río Uruguay en Areas de Plan-
  Celulósicas”). CARU approved the plan on 12 November 2004.

36. On 28 November 2005, Uruguay authorized preparatory work to
gin for the construction of the CMB (ENCE) mill (ground clearing).
n 28 March 2006, the project’s promoters decided to halt the work for
  days. On 21 September 2006, they announced their intention not to
 ild the mill at the planned site on the bank of the River Uruguay.

                      C. Orion (Botnia) Mill
 37. The second industrial project at the root of the dispute before the
ourt was undertaken by “Botnia S.A.” and “Botnia Fray Bentos S.A.”
ereinafter “Botnia”), companies formed under Uruguayan law in 2003
ecially for the purpose by Oy Metsä-Botnia AB, a Finnish company.
 is second pulp mill, called “Orion” (hereinafter the “Orion (Botnia)”
 ll), has been built on the left bank of the River Uruguay, a few kilo-
etres downstream of the site planned for the CMB (ENCE) mill, and
 o near the city of Fray Bentos (see sketch-map No. 2 on p. 35). It has
en operational and functioning since 9 November 2007.

38. After informing the Uruguayan authorities of this industrial
oject in late 2003, the project promoters submitted an application to
em for an initial environmental authorization on 31 March 2004
 d supplemented it on 7 April 2004. Several weeks later, on 29
 d 30 April 2004, CARU members and Botnia representatives met
 ormally. Following that meeting, CARU’s Subcommittee on
ater Quality and Pollution Control suggested on 18 June 2004 that
  tnia expand on the information provided at the meeting. On
    October 2004, CARU held another meeting with Botnia
presentatives and again expressed the need for further information
   Botnia’s application to DINAMA for an initial environmental
 thorization. On 12 November 2004, when approving the water quality
onitoring plan put forward by the CARU Subcommittee on Water
uality and Pollution Control (see paragraph 35 above), CARU decided,
  the proposal of that subcommittee, to ask Uruguay to provide further
 ormation on the application for an initial environmental authoriza-
 n. CARU transmitted this request for further information to Uruguay
  note dated 16 November 2004.

39. On 21 December 2004 DINAMA held a public hearing, attended

                                                                     27

  a CARU adviser, on the Orion (Botnia) project in Fray Bentos.
 NAMA adopted its environmental impact study of the planned Orion
 otnia) mill on 11 February 2005 and recommended that the initial envi-
nmental authorization be granted, subject to certain conditions.
VOTMA issued the initial authorization to Botnia on 14 February 2005
r the construction of the Orion (Botnia) mill and an adjacent port ter-
 nal. At a CARU meeting on 11 March 2005, Argentina questioned
hether the granting of the initial environmental authorization was well-
unded in view of the procedural obligations laid down in the 1975 Stat-
e. Argentina reiterated this position at the CARU meeting on 6 May
 05. On 12 April 2005, Uruguay had in the meantime authorized the
 arance of the future mill site and the associated groundworks.

 40. On 31 May 2005, in pursuance of an agreement made on
May 2005 by the Presidents of the two Parties, their Ministers for For-
  n Affairs created a High-Level Technical Group (hereinafter the
GTAN”, from the Spanish abbreviation for “Grupo Técnico de Alto
 vel”), which was given responsibility for resolving the disputes over the
MB (ENCE) and Orion (Botnia) mills within 180 days. The GTAN
 ld twelve meetings between 3 August 2005 and 30 January 2006, with
e Parties exchanging various documents in the context of this bilateral
 ocess. On 31 January 2006, Uruguay determined that the negotiations
 dertaken within the GTAN had failed ; Argentina did likewise on
February 2006. The Court will return later to the significance of this
 ocess agreed on by the Parties (see paragraphs 132 to 149).

41. On 26 June 2005, Argentina wrote to the President of the Interna-
 nal Bank for Reconstruction and Development to express its concern
 the possibility of the International Finance Corporation (hereinafter
e “IFC”) contributing to the financing of the planned pulp mills. The
C nevertheless decided to provide financial support for the Orion (Bot-
a) mill, but did commission EcoMetrix, a consultancy specializing in
vironmental and industrial matters, to prepare various technical reports
   the planned mill and an environmental impact assessment of it.
 oMetrix was also engaged by the IFC to carry out environmental
onitoring on the IFC’s behalf of the plant once it had been placed in
 vice.
42. On 5 July 2005, Uruguay authorized Botnia to build a port adja-
nt to the Orion (Botnia) mill. This authorization was transmitted to
ARU on 15 August 2005. On 22 August 2005, Uruguay authorized the
nstruction of a chimney and concrete foundations for the Orion (Bot-
a) mill. Further authorizations were granted as the construction of this
 ll proceeded, for example in respect of the waste treatment installa-
 ns. On 13 October 2005, Uruguay transmitted additional documenta-
 n to CARU concerning the port terminal adjacent to the Orion
otnia) mill.

                                                                       28

Argentina repeatedly asked, including at CARU meetings, that the ini-
l work connected with the Orion (Botnia) mill and the CMB (ENCE)
ll should be suspended. At a meeting between the Heads of State of the
rties at Santiago de Chile on 11 March 2006, Uruguay’s President
ked ENCE and Botnia to suspend construction of the mills. ENCE sus-
nded work for 90 days (see paragraph 36 above), Botnia for ten.

43. Argentina referred the present dispute to the Court by Application
ted 4 May 2006. On 24 August 2006, Uruguay authorized the commis-
 ning of the port terminal adjacent to the Orion (Botnia) mill and gave
ARU notice of this on 4 September 2006. On 12 September 2006, Uru-
ay authorized Botnia to extract and use water from the river for indus-
al purposes and formally notified CARU of its authorization on
  October 2006. At the summit of Heads of State and Government of
e Ibero-American countries held in Montevideo in November 2006, the
ng of Spain was asked to endeavour to reconcile the positions of the
 rties ; a negotiated resolution of the dispute did not however result. On
November 2007, Uruguay authorized the commissioning of the Orion
otnia) mill and it began operating the next day. In December 2009, Oy
etsä-Botnia AB transferred its interest in the Orion (Botnia) mill to
PM, another Finnish company.

                                   *
44. In addition, Uruguay authorized Ontur International S.A. to build
d operate a port terminal at Nueva Palmira. The terminal was inaugu-
 ed in August 2007 and, on 16 November 2007, Uruguay transmitted to
ARU a copy of the authorization for its commissioning.

 45. In their written pleadings the Parties have debated whether, in
 ht of the procedural obligations laid down in the 1975 Statute, the
 thorizations for the port terminal were properly issued by Uruguay.
  e Court deems it unnecessary to review the detailed facts leading up to
e construction of the Nueva Palmira terminal, being of the view that
ese port facilities do not fall within the scope of the subject of the dis-
 te before it. Indeed, nowhere in the claims asserted in its Application
 in the submissions in its Memorial or Reply (see paragraphs 22 and 23
 ove) did Argentina explicitly refer to the port terminal at Nueva
 lmira. In its final submissions presented at the hearing on 29 Septem-
r 2009, Argentina again limited the subject-matter of its claims to the
 thorization of the construction of the CMB (ENCE) mill and the
 thorization of the construction and commissioning of “the Botnia mill
 d its associated facilities on the left bank of the River Uruguay”. The
ourt does not consider the port terminal at Nueva Palmira, which lies
me 100 km south of Fray Bentos, downstream of the Orion (Botnia)

                                                                        29

ll (see sketch-map No. 1 on p. 33), and is used by other economic
erators as well, to be a facility “associated” with the mill.

46. The dispute submitted to the Court concerns the interpretation
d application of the 1975 Statute, namely, on the one hand whether
 uguay complied with its procedural obligations under the 1975 Statute
 issuing authorizations for the construction of the CMB (ENCE) mill
 well as for the construction and the commissioning of the Orion (Bot-
a) mill and its adjacent port ; and on the other hand whether Uruguay
s complied with its substantive obligations under the 1975 Statute since
e commissioning of the Orion (Botnia) mill in November 2007.

                                     * *
47. Having thus related the circumstances surrounding the dispute
tween the Parties, the Court will consider the basis and scope of its
 isdiction, including questions relating to the law applicable to the
esent dispute (see paragraphs 48 to 66). It will then examine Argenti-
’s allegations of breaches by Uruguay of procedural obligations (see
ragraphs 67 to 158) and substantive obligations (see paragraphs 159 to
6) laid down in the 1975 Statute. Lastly, the Court will respond to the
 ims presented by the Parties in their final submissions (see para-
aphs 267 to 280).

                                     * *

                II. SCOPE OF THE COURT’S JURISDICTION

48. The Parties are in agreement that the Court’s jurisdiction is based
  Article 36, paragraph 1, of the Statute of the Court and Article 60,
ragraph 1, of the 1975 Statute. The latter reads : “Any dispute concern-
g the interpretation or application of the Treaty 1 and the Statute which
nnot be settled by direct negotiations may be submitted by either party
 the International Court of Justice.” The Parties differ as to whether all
e claims advanced by Argentina fall within the ambit of the comprom-
ory clause.

49. Uruguay acknowledges that the Court’s jurisdiction under the
mpromissory clause extends to claims concerning any pollution or type
 harm caused to the River Uruguay, or to organisms living there, in
olation of the 1975 Statute. Uruguay also acknowledges that claims
ncerning the alleged impact of the operation of the pulp mill on the

 The Montevideo Treaty of 7 April 1961, concerning the boundary constituted by the
ver Uruguay (UNTS, Vol. 635, No. 9074, p. 98 ; footnote added).

                                                                               30

 ality of the waters of the river fall within the compromissory clause.
n the other hand, Uruguay takes the position that Argentina cannot
 y on the compromissory clause to submit claims regarding every type
 environmental damage. Uruguay further argues that Argentina’s con-
ntions concerning air pollution, noise, visual and general nuisance, as
 ll as the specific impact on the tourism sector, allegedly caused by the
 ion (Botnia) mill, do not concern the interpretation or the application
 the 1975 Statute, and the Court therefore lacks jurisdiction over them.

 Uruguay nevertheless does concede that air pollution which has harm-
  effects on the quality of the waters of the river or on the aquatic envi-
nment would fall within the jurisdiction of the Court.
 50. Argentina maintains that Uruguay’s position on the scope of the
ourt’s jurisdiction is too narrow. It contends that the 1975 Statute was
tered into with a view to protect not only the quality of the waters of
e river but more generally its “régime” and the areas affected by it.
 lying on Article 36 of the 1975 Statute, which lays out the obligation
  the parties to co-ordinate measures to avoid any change in the eco-
gical balance and to control harmful factors in the river and the areas
 ected by it, Argentina asserts that the Court has jurisdiction also with
 pect to claims concerning air pollution and even noise and “visual”
 llution. Moreover, Argentina contends that bad odours caused by the
 ion (Botnia) mill negatively affect the use of the river for recreational
 rposes, particularly in the Gualeguaychú resort on its bank of the
 er. This claim, according to Argentina, also falls within the Court’s
 isdiction.
 51. The Court, when addressing various allegations or claims advanced
  Argentina, will have to determine whether they concern “the interpre-
 ion or application” of the 1975 Statute, as its jurisdiction under Article
  thereof covers “[a]ny dispute concerning the interpretation or applica-
 n of the [1961] Treaty and the [1975] Statute”. Argentina has made no
 im to the effect that Uruguay violated obligations under the 1961
 eaty.
 52. In order to determine whether Uruguay has breached its obliga-
 ns under the 1975 Statute, as alleged by Argentina, the Court will have
 interpret its provisions and to determine their scope ratione materiae.

Only those claims advanced by Argentina which are based on the pro-
 ions of the 1975 Statute fall within the Court’s jurisdiction ratione
ateriae under the compromissory clause contained in Article 60.
 though Argentina, when making claims concerning noise and “visual”
 llution allegedly caused by the pulp mill, invokes the provision of Arti-
   36 of the 1975 Statute, the Court sees no basis in it for such claims.
  e plain language of Article 36, which provides that “[t]he parties shall
-ordinate, through the Commission, the necessary measures to avoid
 y change in the ecological balance and to control pests and other
 rmful factors in the river and the areas affected by it”, leaves no doubt

                                                                        31

at it does not address the alleged noise and visual pollution as claimed
 Argentina. Nor does the Court see any other basis in the 1975 Statute
r such claims ; therefore, the claims relating to noise and visual pollu-
 n are manifestly outside the jurisdiction of the Court conferred upon it
 der Article 60.

Similarly, no provision of the 1975 Statute addresses the issue of “bad
 ours” complained of by Argentina. Consequently, for the same reason,
e claim regarding the impact of bad odours on tourism in Argentina
 o falls outside the Court’s jurisdiction. Even if bad odours were to be
bsumed under the issue of air pollution, which will be addressed in
ragraphs 263 and 264 below, the Court notes that Argentina has sub-
tted no evidence as to any relationship between the alleged bad odours
d the aquatic environment of the river.

53. Characterizing the provisions of Articles 1 and 41 of the 1975 Stat-
e as “referral clauses”, Argentina ascribes to them the effect of incor-
 rating into the Statute the obligations of the Parties under general
 ernational law and a number of multilateral conventions pertaining to
e protection of the environment. Consequently, in the view of Argen-
 a, the Court has jurisdiction to determine whether Uruguay has com-
ed with its obligations under certain international conventions.

54. The Court now therefore turns its attention to the issue whether its
 isdiction under Article 60 of the 1975 Statute also encompasses obli-
tions of the Parties under international agreements and general inter-
tional law invoked by Argentina and to the role of such agreements
d general international law in the context of the present case.

55. Argentina asserts that the 1975 Statute constitutes the law appli-
ble to the dispute before the Court, as supplemented so far as its appli-
tion and interpretation are concerned, by various customary principles
d treaties in force between the Parties and referred to in the Statute.
 lying on the rule of treaty interpretation set out in Article 31, para-
aph 3 (c) of the Vienna Convention on the Law of Treaties, Argentina
ntends notably that the 1975 Statute must be interpreted in the light of
 nciples governing the law of international watercourses and principles
 international law ensuring protection of the environment. It asserts
at the 1975 Statute must be interpreted so as to take account of all “rel-
ant rules” of international law applicable in the relations between the
rties, so that the Statute’s interpretation remains current and evolves in
cordance with changes in environmental standards. In this connection
 gentina refers to the principles of equitable, reasonable and non-
urious use of international watercourses, the principles of sustainable
velopment, prevention, precaution and the need to carry out an envi-
nmental impact assessment. It contends that these rules and principles

                                                                       32

e applicable in giving the 1975 Statute a dynamic interpretation,
 hough they neither replace it nor restrict its scope.
 56. Argentina further considers that the Court must require compli-
 ce with the Parties’ treaty obligations referred to in Articles 1 and
  (a) of the 1975 Statute. Argentina maintains that the “referral clauses”
ntained in these articles make it possible to incorporate and apply obli-
 tions arising from other treaties and international agreements binding
  the Parties. To this end, Argentina refers to the 1973 Convention on
ternational Trade in Endangered Species of Wild Fauna and Flora
ereinafter the “CITES Convention”), the 1971 Ramsar Convention on
etlands of International Importance (hereinafter the “Ramsar Conven-
 n”), the 1992 United Nations Convention on Biological Diversity
ereinafter the “Biodiversity Convention”), and the 2001 Stockholm
onvention on Persistent Organic Pollutants (hereinafter the “POPs
onvention”). It asserts that these conventional obligations are in addi-
 n to the obligations arising under the 1975 Statute, and observance of
em should be ensured when application of the Statute is being consid-
ed. Argentina maintains that it is only where “more specific rules of the
975] Statute (lex specialis)” derogate from them that the instruments
  which the Statute refers should not be applied.

57. Uruguay likewise considers that the 1975 Statute must be inter-
eted in the light of general international law and it observes that the
 rties concur on this point. It maintains however that its interpretation
 the 1975 Statute accords with the various general principles of the law
  international watercourses and of international environmental law,
en if its understanding of these principles does not entirely correspond
  that of Argentina. Uruguay considers that whether Articles 1 and
  (a) of the 1975 Statute can be read as a referral to other treaties in
rce between the Parties has no bearing in the present case, because con-
ntions relied on by Argentina are either irrelevant, or Uruguay cannot
  found to have violated any other conventional obligations. In any
ent, the Court would lack jurisdiction to rule on alleged breaches of
 ernational obligations which are not contained in the 1975 Statute.

58. The Court will first address the issue whether Articles 1 and 41 (a)
n be read as incorporating into the 1975 Statute the obligations of the
rties under the various multilateral conventions relied upon by Argen-
a.
59. Article 1 of the 1975 Statute reads as follows :

      “The parties agree on this Statute, in implementation of the pro-
   visions of Article 7 of the Treaty concerning the Boundary Consti-
   tuted by the River Uruguay of 7 April 1961, in order to establish the
   joint machinery necessary for the optimum and rational utilization

                                                                       33

   of the River Uruguay, in strict observance of the rights and obliga-
   tions arising from treaties and other international agreements in
   force for each of the parties.” (UNTS, Vol. 1295, No. I-21425,
   p. 340 ; footnote omitted.)
 Article 1 sets out the purpose of the 1975 Statute. The Parties con-
uded it in order to establish the joint machinery necessary for the
  ional and optimum utilization of the River Uruguay. It is true that this
  icle contains a reference to “the rights and obligations arising from
  aties and other international agreements in force for each of the
 rties”. This reference, however, does not suggest that the Parties sought
  make compliance with their obligations under other treaties one of
 eir duties under the 1975 Statute ; rather, the reference to other treaties
mphasizes that the agreement of the Parties on the Statute is reached
  implementation of the provisions of Article 7 of the 1961 Treaty
 d “in strict observance of the rights and obligations arising from
  aties and other international agreements in force for each of the
 rties” (emphasis added). While the conjunction “and” is missing
om the English and French translations of the 1975 Statute, as
 blished in the United Nations Treaty Series (ibid., p. 340 and p. 348),
  s contained in the Spanish text of the Statute, which is the authentic
xt and reads as follows :
      “Las partes acuerdan el presente Estatuto, en cumplimiento de lo
   dispuesto en el Artículo 7 del Tratado de Límites en el Río Uruguay,
   de 7 de Abril de 1961 con el fin de establecer los mecanismos
   comunes necesarios para el óptimo y racional aprovechamiento del
   Río Uruguay, y en estricta observancia de los derechos y obliga-
   ciones emergentes de los tratados y demás compromisos internacion-
   ales vigentes para cualquiera de las partes.” (Ibid., p. 332 ; emphasis
   added.)
The presence of the conjunction in the Spanish text suggests that the
 use “in strict observance of the rights and obligations arising from
 aties and other international agreements in force for each of the
rties” is linked to and is to be read with the first part of Article 1, i.e.,
]he parties agree on this Statute, in implementation of the provisions of
 ticle 7 of the Treaty concerning the Boundary Constituted by the
ver Uruguay”.
60. There is one additional element in the language of Article 1 of
e 1975 Statute which should be noted. It mentions “treaties and
her international agreements in force for each of the parties” (in
 anish original “tratados y demás compromisos internacionales vig-
tes para cualquiera de las partes” ; emphasis added). In the French
 nslation, this part of Article 1 reads “traités et autres engagements
 ernationaux en vigueur à l’égard de l’une ou l’autre des parties”
mphasis added).
The fact that Article 1 does not require that the “treaties and other

                                                                          34

 ernational agreements” should be in force between the two parties thus
 arly indicates that the 1975 Statute takes account of the prior commit-
ents of each of the parties which have a bearing on it.
61. Article 41 of the 1975 Statute, paragraph (a) of which Argentina
nsiders as constituting another “referral clause” incorporating the obli-
tions under international agreements into the Statute, reads as follows :
     “Without prejudice to the functions assigned to the Commission
  in this respect, the parties undertake :
  (a) to protect and preserve the aquatic environment and, in par-
       ticular, to prevent its pollution, by prescribing appropriate rules
       and [adopting appropriate] measures in accordance with appli-
       cable international agreements and in keeping, where relevant,
       with the guidelines and recommendations of international tech-
       nical bodies ;
  (b) not to reduce in their respective legal systems :
       1) the technical requirements in force for preventing water pol-
           lution, and
       2) the severity of the penalties established for violations ;
  (c) to inform one another of any rules which they plan to prescribe
       with regard to water pollution in order to establish equivalent
       rules in their respective legal systems.” (Emphasis added.)

62. The Court observes that the words “adopting appropriate” do not
pear in the English translation while they appear in the original Span-
  text (“dictando las normas y adoptando las medidas apropiadas”).
 sing itself on the original Spanish text, it is difficult for the Court to see
w this provision could be construed as a “referral clause” having the
ect of incorporating the obligations of the parties under international
reements and other norms envisaged within the ambit of the 1975
atute.

The purpose of the provision in Article 41 (a) is to protect and pre-
  ve the aquatic environment by requiring each of the parties to enact
  es and to adopt appropriate measures. Article 41 (a) distinguishes
tween applicable international agreements and the guidelines and recom-
endations of international technical bodies. While the former are legally
nding and therefore the domestic rules and regulations enacted and the
easures adopted by the State have to comply with them, the latter, not
ing formally binding, are, to the extent they are relevant, to be taken
 o account by the State so that the domestic rules and regulations and
e measures it adopts are compatible (“con adecuación”) with those
 idelines and recommendations. However, Article 41 does not incorpo-
  e international agreements as such into the 1975 Statute but rather sets
 ligations for the parties to exercise their regulatory powers, in con-
rmity with applicable international agreements, for the protection and

                                                                            35

eservation of the aquatic environment of the River Uruguay. Under
 ticle 41 (b) the existing requirements for preventing water pollution
d the severity of the penalties are not to be reduced. Finally, para-
aph (c) of Article 41 concerns the obligation to inform the other party
 plans to prescribe rules on water pollution.

63. The Court concludes that there is no basis in the text of Article 41
  the 1975 Statute for the contention that it constitutes a “referral
 use”. Consequently, the various multilateral conventions relied on by
 gentina are not, as such, incorporated in the 1975 Statute. For that
ason, they do not fall within the scope of the compromissory clause and
erefore the Court has no jurisdiction to rule whether Uruguay has com-
 ed with its obligations thereunder.

64. The Court next briefly turns to the issue of how the 1975 Statute is
be interpreted. The Parties concur as to the 1975 Statute’s origin and
torical context, although they differ as to the nature and general tenor
the Statute and the procedural and substantive obligations therein.

The Parties nevertheless are in agreement that the 1975 Statute is to be
 erpreted in accordance with rules of customary international law on
 aty interpretation, as codified in Article 31 of the Vienna Convention
  the Law of Treaties.
65. The Court has had recourse to these rules when it has had to inter-
et the provisions of treaties and international agreements concluded
fore the entry into force of the Vienna Convention on the Law of Trea-
s in 1980 (see, e.g., Territorial Dispute (Libyan Arab Jamahiriya/
 ad), Judgment, I.C.J. Reports 1994, p. 21, para. 41 ; Kasikili/Sedudu
and (Botswana/Namibia), Judgment, I.C.J. Reports 1999 (II), p. 1059,
ra. 18).
The 1975 Statute is also a treaty which predates the entry into force of
e Vienna Convention on the Law of Treaties. In interpreting the terms
 the 1975 Statute, the Court will have recourse to the customary rules
  treaty interpretation as reflected in Article 31 of the Vienna Conven-
 n. Accordingly the 1975 Statute is to be “interpreted in good faith in
cordance with the ordinary meaning to be given to the terms of the
 atute] in their context and in light of its object and purpose”. That
 erpretation will also take into account, together with the context, “any
evant rules of international law applicable in the relations between the
rties”.
66. In the interpretation of the 1975 Statute, taking account of rele-
nt rules of international law applicable in the relations between the
 rties, whether these are rules of general international law or contained
 multilateral conventions to which the two States are parties, neverthe-
s has no bearing on the scope of the jurisdiction conferred on the

                                                                      36

ourt under Article 60 of the 1975 Statute, which remains confined to
 putes concerning the interpretation or application of the Statute.

                                 * *

      III. THE ALLEGED BREACH OF PROCEDURAL OBLIGATIONS

67. The Application filed by Argentina on 4 May 2006 concerns the
eged breach by Uruguay of both procedural and substantive obliga-
 ns laid down in the 1975 Statute. The Court will start by considering
e alleged breach of procedural obligations under Articles 7 to 12 of the
75 Statute, in relation to the (CMB) ENCE and Orion (Botnia) mill
ojects and the facilities associated with the latter, on the left bank of
e River Uruguay near the city of Fray Bentos.

68. Argentina takes the view that the procedural obligations were
rinsically linked to the substantive obligations laid down by the
75 Statute, and that a breach of the former entailed a breach of the
ter.
With regard to the procedural obligations, these are said by Argentina
 constitute an integrated and indivisible whole in which CARU, as an
ganization, plays an essential role.
Consequently, according to Argentina, Uruguay could not invoke
her procedural arrangements so as to derogate from the procedural
ligations laid down by the 1975 Statute, except by mutual consent.

 69. Argentina argues that, at the end of the procedural mechanism
ovided for by the 1975 Statute, and in the absence of agreement
tween the Parties, the latter have no choice but to submit the matter to
e Court under the terms of Articles 12 and 60 of the Statute, with Uru-
 ay being unable to proceed with the construction of the planned mills
 til the Court has delivered its Judgment.
 70. Following the lines of the argument put forward by the Applicant,
e Court will examine in turn the following four points : the links
tween the procedural obligations and the substantive obligations (A) ;
e procedural obligations and their interrelation with each other (B) ;
hether the Parties agreed to derogate from the procedural obligations
  out in the 1975 Statute (C) ; and Uruguay’s obligations at the end of
e negotiation period (D).

         A. The Links between the Procedural Obligations
                 and the Substantive Obligations
71. Argentina maintains that the procedural provisions laid down in
ticles 7 to 12 of the 1975 Statute are aimed at ensuring “the optimum

                                                                      37

 d rational utilization of the [r]iver” (Article 1), just as are the provi-
 ns concerning use of water, the conservation, utilization and develop-
ent of other natural resources, pollution and research. The aim is also
 d to be to prevent the Parties from acting unilaterally and without
gard for earlier or current uses of the river. According to Argentina,
 y disregarding of this machinery would therefore undermine the object
 d purpose of the 1975 Statute ; indeed the “optimum and rational
 lization of the [r]iver” would not be ensured, as this could only
  achieved in accordance with the procedures laid down under the
atute.

72. It follows, according to Argentina, that a breach of the procedural
ligations automatically entails a breach of the substantive obligations,
ce the two categories of obligations are indivisible. Such a position is
d to be supported by the Order of the Court of 13 July 2006, according
which the 1975 Statute created “a comprehensive régime”.

73. Uruguay similarly takes the view that the procedural obligations
e intended to facilitate the performance of the substantive obligations,
e former being a means rather than an end. It too points out that Arti-
  1 of the 1975 Statute defines its object and purpose.

 74. However, Uruguay rejects Argentina’s argument as artificial, since
appears to mix procedural and substantive questions with the aim of
eating the belief that the breach of procedural obligations necessarily
tails the breach of substantive ones. According to Uruguay, it is for the
ourt to determine the breach, in itself, of each of these categories of
 ligations, and to draw the necessary conclusions in each case in terms
 responsibility and reparation.

75. The Court notes that the object and purpose of the 1975 Statute,
  forth in Article 1, is for the Parties to achieve “the optimum and
 ional utilization of the River Uruguay” by means of the “joint machin-
y” for co-operation, which consists of both CARU and the procedural
ovisions contained in Articles 7 to 12 of the Statute.
The Court has observed in this respect, in its Order of 13 July 2006,
at such use should allow for sustainable development which takes
count of “the need to safeguard the continued conservation of the river
vironment and the rights of economic development of the riparian
ates” (Pulp Mills on the River Uruguay (Argentina v. Uruguay), Pro-
 ional Measures, Order of 13 July 2006, I.C.J. Reports 2006, p. 133,
 ra. 80).
76. In the Gabčikovo-Nagymaros case, the Court, after recalling that
 ]his need to reconcile economic development with protection of the
vironment is aptly expressed in the concept of sustainable develop-
ent”, added that “[i]t is for the Parties themselves to find an agreed
 ution that takes account of the objectives of the Treaty” (Gabčíkovo-

                                                                        38

agymaros Project (Hungary/Slovakia), Judgment, I.C.J. Reports 1997,
  78, paras. 140-141).
 77. The Court observes that it is by co-operating that the States con-
 rned can jointly manage the risks of damage to the environment that
  ght be created by the plans initiated by one or other of them, so as to
 event the damage in question, through the performance of both the
 ocedural and the substantive obligations laid down by the 1975 Stat-
 e. However, whereas the substantive obligations are frequently worded
  broad terms, the procedural obligations are narrower and more spe-
fic, so as to facilitate the implementation of the 1975 Statute through a
 ocess of continuous consultation between the parties concerned. The
ourt has described the régime put in place by the 1975 Statute as a
 omprehensive and progressive régime” (Pulp Mills on the River Uru-
 ay (Argentina v. Uruguay), Provisional Measures, Order of 13 July
 06, I.C.J. Reports 2006, p. 133, para. 81), since the two categories of
  ligations mentioned above complement one another perfectly, enabling
 e parties to achieve the object of the Statute which they set themselves
  Article 1.

78. The Court notes that the 1975 Statute created CARU and estab-
hed procedures in connection with that institution, so as to enable the
rties to fulfil their substantive obligations. However, nowhere does the
75 Statute indicate that a party may fulfil its substantive obligations by
mplying solely with its procedural obligations, nor that a breach of
ocedural obligations automatically entails the breach of substantive
 es.
Likewise, the fact that the parties have complied with their substantive
 ligations does not mean that they are deemed to have complied ipso
cto with their procedural obligations, or are excused from doing so.
oreover, the link between these two categories of obligations can also
  broken, in fact, when a party which has not complied with its proce-
 ral obligations subsequently abandons the implementation of its
anned activity.
79. The Court considers, as a result of the above, that there is indeed
 unctional link, in regard to prevention, between the two categories of
 ligations laid down by the 1975 Statute, but that link does not prevent
e States parties from being required to answer for those obligations
parately, according to their specific content, and to assume, if neces-
ry, the responsibility resulting from the breach of them, according to
e circumstances.

       B. The Procedural Obligations and Their Interrelation
 80. The 1975 Statute imposes on a party which is planning certain
tivities, set out in Article 7, first paragraph, procedural obligations
hose content, interrelation and time-limits are specified as follows in
 ticles 7 to 12 :

                                                                       39

                              “Article 7
  If one party plans to construct new channels, substantially modify
or alter existing ones or carry out any other works which are liable
to affect navigation, the régime of the river or the quality of its
waters, it shall notify the Commission, which shall determine on a
preliminary basis and within a maximum period of 30 days whether
the plan might cause significant damage to the other party.

   If the Commission finds this to be the case or if a decision cannot
be reached in that regard, the party concerned shall notify the other
party of the plan through the said Commission.
   Such notification shall describe the main aspects of the work and,
where appropriate, how it is to be carried out and shall include any
other technical data that will enable the notified party to assess the
probable impact of such works on navigation, the régime of the river
or the quality of its waters.
                               Article 8
   The notified party shall have a period of 180 days in which to
respond in connection with the plan, starting from the date on which
its delegation to the Commission receives the notification.
   Should the documentation referred to in Article 7 be incomplete,
the notified party shall have 30 days in which to so inform, through
the Commission, the party which plans to carry out the work.

   The period of 180 days mentioned above shall begin on the date
on which the delegation of the notified party receives the full docu-
mentation.
   This period may be extended at the discretion of the Commission
if the complexity of the plan so requires.
                              Article 9
   If the notified party raises no objections or does not respond
within the period established in Article 8, the other party may carry
out or authorize the work planned.
                              Article 10
   The notified party shall have the right to inspect the works being
carried out in order to determine whether they conform to the plan
submitted.
                              Article 11
   Should the notified party come to the conclusion that the execu-
tion of the work or the programme of operations might significantly
impair navigation, the régime of the river or the quality of its waters,
it shall so notify the other party, through the Commission, within
the period of 180 days established in Article 8.
   Such notification shall specify which aspects of the work or the

                                                                     40

  programme of operations might significantly impair navigation, the
  régime of the river or the quality of its waters, the technical reasons
  on which this conclusion is based and the changes suggested to the
  plan or programme of operations.

                                 Article 12
     Should the parties fail to reach agreement within 180 days follow-
  ing the notification referred to in Article 11, the procedure indicated
  in Chapter XV shall be followed.”
81. The original Spanish text of Article 7 of the 1975 Statute reads as
lows :
     “La parte que proyecte la construcción de nuevos canales, la
  modificación o alteración significativa de los ya existentes o la real-
  ización de cualesquiera otras obras de entidad suficiente para afectar
  la navegación, el régimen del Río o la calidad de sus aguas, deberá
  comunicarlo a la Comisión, la cual determinará sumariamente, y en
  un plazo máximo de treinta días, si el proyecto puede producir per-
  juicio sensible a la otra parte.
     Si así se resolviere o no se llegare a una decisión al respecto, la
  parte interesada deberá notificar el proyecto a la otra parte a través
  de la misma Comisión.
     En la notificación deberán figurar los aspectos esenciales de la
  obra y, si fuere el caso, el modo de su operación y los demás datos
  técnicos que permitan a la parte notificada hacer una evaluación del
  efecto probable que la obra ocasionará a la navegación, al régimen
  del Río o a la calidad de sus aguas.”
The Court notes that, just as the original Spanish text, the French
 nslation of this Article (see paragraph 80 above) distinguishes between
e obligation to inform (“comunicar”) CARU of any plan falling within
  purview (first paragraph) and the obligation to notify (“notificar”) the
her party (second paragraph). By contrast, the English translation uses
e same verb “notify” in respect of both obligations. In order to con-
rm to the original Spanish text, the Court will use in both linguistic
rsions of this Judgment the verb “inform” for the obligation set out in
e first paragraph of Article 7 and the verb “notify” for the obligation
  out in the second and third paragraphs.
The Court considers that the procedural obligations of informing,
 tifying and negotiating constitute an appropriate means, accepted by
e Parties, of achieving the objective which they set themselves in Arti-
  1 of the 1975 Statute. These obligations are all the more vital when a
ared resource is at issue, as in the case of the River Uruguay, which can
 ly be protected through close and continuous co-operation between
e riparian States.
82. According to Argentina, by failing to comply with the initial obli-
tion (Article 7, first paragraph, of the 1975 Statute) to refer the matter

                                                                       41

  CARU, Uruguay frustrated all the procedures laid down in Articles 7
   12 of the Statute. In addition, by failing to notify Argentina of the
ans for the CMB (ENCE) and Orion (Botnia) mills, through CARU,
 th all the necessary documentation, Uruguay is said not to have com-
 ed with Article 7, second and third paragraphs. Argentina adds that
  ormal contacts which it or CARU may have had with the companies
  question cannot serve as a substitute for Uruguay referring the matter
  CARU and notifying Argentina of the projects through the Commis-
  n. Argentina concludes that Uruguay has breached all of its procedural
 ligations under the terms of Articles 7 to 12 of the 1975 Statute.
 Uruguay, for its part, considers that referring the matter to CARU
  es not impose so great a constraint as Argentina contends and that the
 rties may agree, by mutual consent, to use different channels by
mploying other procedural arrangements in order to engage in co-
  eration. It concludes from this that it has not breached the procedural
  ligations laid down by the 1975 Statute, even if it has performed them
 thout following to the letter the formal process set out therein.
 83. The Court will first examine the nature and role of CARU, and
 en consider whether Uruguay has complied with its obligations to
  orm CARU and to notify Argentina of its plans.

  The nature and role of CARU
84. Uruguay takes the view that CARU, like other river commissions,
not a body with autonomous powers, but rather a mechanism estab-
hed to facilitate co-operation between the Parties. It adds that the
ates which have created these river commissions are free to go outside
e joint mechanism when it suits their purposes, and that they often do
  According to Uruguay, since CARU is not empowered to act outside
e will of the Parties, the latter are free to do directly what they have
cided to do through the Commission, and in particular may agree not
 inform it in the manner provided for in Article 7 of the 1975 Statute.
 uguay maintains that that is precisely what happened in the present
se : the two States agreed to dispense with the preliminary review by
ARU and to proceed immediately to direct negotiations.

85. For Argentina, on the other hand, the 1975 Statute is not merely
 bilateral treaty imposing reciprocal obligations on the parties ; it
 ablishes an institutional framework for close and ongoing co-op-
ation, the core and essence of which is CARU. For Argentina,
ARU is the key body for co-ordination between the Parties in virtually
  areas covered by the 1975 Statute. By failing to fulfil its obligations
 this respect, Uruguay is said to be calling the 1975 Statute funda-
entally into question.
86. The Court recalls that it has already described CARU as

                                                                      42

   “a joint mechanism with regulatory, executive, administrative, tech-
   nical and conciliatory functions, entrusted with the proper imple-
   mentation of the rules contained in the 1975 Statute governing the
   management of the shared river resource ; . . . [a] mechanism [which]
   constitutes a very important part of that treaty régime” (Pulp Mills
   on the River Uruguay (Argentina v. Uruguay), Provisional Meas-
   ures, Order of 13 July 2006, I.C.J. Reports 2006, pp. 133-134,
   para. 81).
87. The Court notes, first, that CARU, in accordance with Article 50
 the 1975 Statute, was endowed with legal personality “in order to per-
rm its functions” and that the parties to the 1975 Statute undertook to
ovide it with “the necessary resources and all the information and
cilities essential to its operations”. Consequently, far from being merely
 ransmission mechanism between the parties, CARU has a permanent
 stence of its own ; it exercises rights and also bears duties in carrying
 t the functions attributed to it by the 1975 Statute.

88. While the decisions of the Commission must be adopted by com-
on accord between the riparian States (Article 55), these are prepared
d implemented by a secretariat whose staff enjoy privileges and immu-
 ies. Moreover, CARU is able to decentralize its various functions by
 ting up whatever subsidiary bodies it deems necessary (Article 52).

89. The Court observes that, like any international organization with
al personality, CARU is entitled to exercise the powers assigned
 it by the 1975 Statute and which are necessary to achieve the
ject and purpose of the latter, namely, “the optimum and rational
lization of the River Uruguay” (Article 1). As the Court has pointed
t,
   “[i]nternational organizations are governed by the ‘principle of
   speciality’, that is to say, they are invested by the States which
   create them with powers, the limits of which are a function of
   the common interests whose promotion those States entrust to
   them” (Legality of the Use by a State of Nuclear Weapons in
   Armed Conflict, Advisory Opinion, I.C.J. Reports 1996 (I), p. 78,
   para. 25).
 is also applies of course to organizations, which like CARU, only have
 o member States.
 90. Since CARU serves as a framework for consultation between the
 rties, particularly in the case of the planned works contemplated in
 ticle 7, first paragraph, of the 1975 Statute, neither of them may depart
om that framework unilaterally, as they see fit, and put other channels
 communication in its place. By creating CARU and investing it with
  the resources necessary for its operation, the parties have sought to
ovide the best possible guarantees of stability, continuity and effective-

                                                                       43

ss for their desire to co-operate in ensuring “the optimum and rational
 lization of the River Uruguay”.
91. That is why CARU plays a central role in the 1975 Statute and
nnot be reduced to merely an optional mechanism available to the
rties which each may use or not, as it pleases. CARU operates at all
 els of utilization of the river, whether concerning the prevention of
 nsboundary harm that may result from planned activities ; the use of
 ter, on which it receives reports from the parties and verifies whether
e developments taken together are liable to cause significant damage
rticles 27 and 28) ; the avoidance of any change in the ecological bal-
ce (Article 36) ; scientific studies and research carried out by one party
thin the jurisdiction of the other (Article 44) ; the exercise of the right
 law enforcement (Article 46) ; or the right of navigation (Article 48).

 92. Furthermore, CARU has been given the function of drawing up
 es in many areas associated with the joint management of the river and
ted in Article 56 of the 1975 Statute. Lastly, at the proposal of either
 rty, the Commission can act as a conciliation body in any dispute
hich may arise between the parties (Article 58).
 93. Consequently, the Court considers that, because of the scale and
versity of the functions they have assigned to CARU, the Parties
 ended to make that international organization a central component in
e fulfilment of their obligations to co-operate as laid down by the
 75 Statute.

 Uruguay’s obligation to inform CARU
94. The Court notes that the obligation of the State initiating the
anned activity to inform CARU constitutes the first stage in the proce-
 ral mechanism as a whole which allows the two parties to achieve the
 ject of the 1975 Statute, namely, the optimum and rational utilization
  the River Uruguay”. This stage, provided for in Article 7, first para-
aph, involves the State which is initiating the planned activity inform-
g CARU thereof, so that the latter can determine “on a preliminary
sis” and within a maximum period of 30 days whether the plan might
use significant damage to the other party.
95. To enable the remainder of the procedure to take its course, the
rties have included alternative conditions in the 1975 Statute : either
at the activity planned by one party should be liable, in CARU’s
 inion, to cause significant damage to the other, creating an obligation
 prevention for the first party to eliminate or minimize the risk, in con-
 tation with the other party ; or that CARU, having been duly informed,
ould not have reached a decision in that regard within the prescribed
riod.
96. The Court notes that the Parties are agreed in considering that the
o planned mills were works of sufficient importance to fall within the
ope of Article 7 of the 1975 Statute, and thus for CARU to have been

                                                                        44

 ormed of them. The same applies to the plan to construct a port ter-
 nal at Fray Bentos for the exclusive use of the Orion (Botnia) mill,
hich included dredging work and use of the river bed.

 97. However, the Court observes that the Parties disagree on whether
ere is an obligation to inform CARU in respect of the extraction and
e of water from the river for industrial purposes by the Orion (Botnia)
 ll. Argentina takes the view that the authorization granted by the Uru-
 ayan Ministry of Transport and Public Works on 12 September 2006
ncerns an activity of sufficient importance (“entidad suficiente”) to
 ect the régime of the river or the quality of its waters and that, in this
atter, Uruguay should have followed the procedure laid down in Arti-
 s 7 to 12 of the 1975 Statute. For its part, Uruguay maintains that this
tivity forms an integral part of the Orion (Botnia) mill project as a
hole, and that the 1975 Statute does not require CARU to be informed
 each step in furtherance of the planned works.
 98. The Court points out that while the Parties are agreed in recogniz-
g that CARU should have been informed of the two planned mills and
e plan to construct the port terminal at Fray Bentos, they nonetheless
 fer as regards the content of the information which should be provided
 CARU and as to when this should take place.
 99. Argentina has argued that the content of the obligation to inform
ust be determined in the light of its objective, which is to prevent
reats to navigation, the régime of the river or the quality of the waters.
 cording to Argentina, the plan which CARU must be informed of may
  at a very early stage, since it is simply a matter of allowing the Com-
 ssion to “determine on a preliminary basis”, within a very short period
 30 days, whether the plan “might cause significant damage to the other
 rty”. It is only in the following phase of the procedure that the sub-
 nce of the obligation to inform is said to become more extensive. In
 gentina’s view, however, CARU must be informed prior to the authori-
tion or implementation of a project on the River Uruguay.
 100. Citing the terms of Article 7, first paragraph, of the 1975 Statute,
 uguay gives a different interpretation of it, taking the view that the
quirement to inform CARU specified by this provision cannot occur in
e very early stages of planning, because there could not be sufficient
 ormation available to the Commission for it to determine whether or
 t the plan might cause significant damage to the other State. For that,
cording to Uruguay, the project would have to have reached a stage
here all the technical data on it are available. As the Court will consider
rther below, Uruguay seeks to link the content of the information to
e time when it should be provided, which may even be after the State
ncerned has granted an initial environmental authorization.
 101. The Court points out that the principle of prevention, as a cus-
mary rule, has its origins in the due diligence that is required of a State
 its territory. It is “every State’s obligation not to allow knowingly its
 ritory to be used for acts contrary to the rights of other States” (Corfu

                                                                        45

 annel (United Kingdom v. Albania), Merits, Judgment, I.C.J. Reports
49, p. 22). A State is thus obliged to use all the means at its disposal in
der to avoid activities which take place in its territory, or in any area
 der its jurisdiction, causing significant damage to the environment of
 other State. This Court has established that this obligation “is now
 rt of the corpus of international law relating to the environment”
egality of the Threat or Use of Nuclear Weapons, Advisory Opinion,
C.J. Reports 1996 (I), p. 242, para. 29).

102. In the view of the Court, the obligation to inform CARU allows
r the initiation of co-operation between the Parties which is necessary
 order to fulfil the obligation of prevention. This first procedural stage
 ults in the 1975 Statute not being applied to activities which would
 pear to cause damage only to the State in whose territory they are car-
 d out.
103. The Court observes that with regard to the River Uruguay, which
nstitutes a shared resource, “significant damage to the other party”
 rticle 7, first paragraph, of the 1975 Statute) may result from impair-
ent of navigation, the régime of the river or the quality of its waters.
oreover, Article 27 of the 1975 Statute stipulates that :
   “[t]he right of each party to use the waters of the river, within its
   jurisdiction, for domestic, sanitary, industrial and agricultural pur-
   poses shall be exercised without prejudice to the application of the
   procedure laid down in Articles 7 to 12 when the use is liable to
   affect the régime of the river or the quality of its waters”.

104. The Court notes that, in accordance with the terms of Article 7,
st paragraph, the information which must be provided to CARU, at
 s initial stage of the procedure, has to enable it to determine swiftly
d on a preliminary basis whether the plan might cause significant dam-
e to the other party. For CARU, at this stage, it is a question of decid-
g whether or not the plan falls under the co-operation procedure laid
 wn by the 1975 Statute, and not of pronouncing on its actual impact
  the river and the quality of its waters. This explains, in the opinion of
e Court, the difference between the terminology of the first paragraph
 Article 7, concerning the requirement to inform CARU, and that of
e third paragraph, concerning the content of the notification to be
dressed to the other party at a later stage, enabling it “to assess the
obable impact of such works on navigation, the régime of the river or
e quality of its waters”.
105. The Court considers that the State planning activities referred to
 Article 7 of the Statute is required to inform CARU as soon as it is in
 ssession of a plan which is sufficiently developed to enable CARU to
ake the preliminary assessment (required by paragraph 1 of that provi-
 n) of whether the proposed works might cause significant damage to
e other party. At that stage, the information provided will not neces-

                                                                        46

rily consist of a full assessment of the environmental impact of the
oject, which will often require further time and resources, although,
here more complete information is available, this should, of course, be
  nsmitted to CARU to give it the best possible basis on which to make
  preliminary assessment. In any event, the duty to inform CARU will
come applicable at the stage when the relevant authority has had the
oject referred to it with the aim of obtaining initial environmental
 thorization and before the granting of that authorization.
 106. The Court observes that, in the present case, Uruguay did not
  nsmit to CARU the information required by Article 7, first paragraph,
  respect of the CMB (ENCE) and Orion (Botnia) mills, despite the
quests made to it by the Commission to that effect on several occa-
  ns, in particular on 17 October 2002 and 21 April 2003 with regard to
e CMB (ENCE) mill, and on 16 November 2004 with regard to the
 ion (Botnia) mill. Uruguay merely sent CARU, on 14 May 2003, a
mmary for public release of the environmental impact assessment for
e CMB (ENCE) mill. CARU considered this document to be inad-
uate and again requested further information from Uruguay on
  August 2003 and 12 September 2003. Moreover, Uruguay did not
  nsmit any document to CARU regarding the Orion (Botnia) mill.
onsequently, Uruguay issued the initial environmental authorizations
  CMB on 9 October 2003 and to Botnia on 14 February 2005 without
mplying with the procedure laid down in Article 7, first paragraph.
  uguay therefore came to a decision on the environmental impact of the
ojects without involving CARU, thereby simply giving effect to Arti-
  17, third paragraph, of Uruguayan Decree No. 435/994 of 21 Septem-
r 1994, Environmental Impact Assessment Regulation, according to
hich the Ministry of Housing, Land Use Planning and Environmental
 fairs may grant the initial environmental authorization provided that
e adverse environmental impacts of the project remain within accept-
 le limits.
 107. The Court further notes that on 12 April 2005 Uruguay granted
  authorization to Botnia for the first phase of the construction of the
 ion (Botnia) mill and, on 5 July 2005, an authorization to construct
 port terminal for its exclusive use and to utilize the river bed for
dustrial purposes, without informing CARU of these projects in
 vance.
 108. With regard to the extraction and use of water from the river, of
hich CARU should have first been informed, according to Argentina,
e Court takes the view that this is an activity which forms an integral
 rt of the commissioning of the Orion (Botnia) mill and therefore did
 t require a separate referral to CARU.
 109. However, Uruguay maintains that CARU was made aware of the
ans for the mills by representatives of ENCE on 8 July 2002, and no
 er than 29 April 2004 by representatives of Botnia, before the initial
vironmental authorizations were issued. Argentina, for its part, consid-
   that these so-called private dealings, whatever form they may have

                                                                     47

ken, do not constitute performance of the obligation imposed on the
rties by Article 7, first paragraph.
110. The Court considers that the information on the plans for the
lls which reached CARU via the companies concerned or from other
n-governmental sources cannot substitute for the obligation to inform
d down in Article 7, first paragraph, of the 1975 Statute, which is
rne by the party planning to construct the works referred to in that
ovision. Similarly, in the case concerning Certain Questions of Mutual
 sistance in Criminal Matters (Djibouti v. France), the Court observed
at
  “[i]f the information eventually came to Djibouti through the press,
  the information disseminated in this way could not be taken into
  account for the purposes of the application of Article 17 [of the Con-
  vention on Mutual Assistance in Criminal Matters between the two
  countries, providing that ‘[r]easons shall be given for any refusal of
  mutual assistance’]” (Judgment, I.C.J. Reports 2008, p. 231,
  para. 150).
111. Consequently, the Court concludes from the above that Uruguay,
 not informing CARU of the planned works before the issuing of the
tial environmental authorizations for each of the mills and for the port
 minal adjacent to the Orion (Botnia) mill, has failed to comply with
e obligation imposed on it by Article 7, first paragraph, of the 1975 Stat-
e.

 Uruguay’s obligation to notify the plans to the other party
112. The Court notes that, under the terms of Article 7, second para-
aph, of the 1975 Statute, if CARU decides that the plan might cause
 nificant damage to the other party or if a decision cannot be reached in
at regard, “the party concerned shall notify the other party of this plan
rough the said Commission”.
Article 7, third paragraph, of the 1975 Statute sets out in detail the
ntent of this notification, which
  “shall describe the main aspects of the work and . . . any other tech-
  nical data that will enable the notified party to assess the probable
  impact of such works on navigation, the régime of the river or the
  quality of its waters”.
113. In the opinion of the Court, the obligation to notify is intended to
eate the conditions for successful co-operation between the parties, ena-
 ng them to assess the plan’s impact on the river on the basis of the
 lest possible information and, if necessary, to negotiate the adjust-
ents needed to avoid the potential damage that it might cause.

114. Article 8 stipulates a period of 180 days, which may be extended
 the Commission, for the notified party to respond in connection with

                                                                        48

e plan, subject to it requesting the other party, through the Commis-
 n, to supplement as necessary the documentation it has provided.

If the notified party raises no objections, the other party may carry out
 authorize the work (Article 9). Otherwise, the former must notify the
ter of those aspects of the work which may cause it damage and of the
ggested changes (Article 11), thereby opening a further 180-day period
 negotiation in which to reach an agreement (Article 12).

 115. The obligation to notify is therefore an essential part of the proc-
  leading the parties to consult in order to assess the risks of the plan
 d to negotiate possible changes which may eliminate those risks or
 nimize their effects.
 116. The Parties agree on the need for a full environmental impact
sessment in order to assess any significant damage which might be
used by a plan.
 117. Uruguay takes the view that such assessments were carried out in
cordance with its legislation (Decree No. 435/994 of 21 September 1994,
 vironmental Impact Assessment Regulation), submitted to DINAMA
r consideration and transmitted to Argentina on 7 November 2003 in
e case of the CMB (ENCE) project and on 19 August 2005 for the
 ion (Botnia) project. According to Uruguay, DINAMA asked the
mpanies concerned for all the additional information that was required
 supplement the original environmental impact assessments submitted
 it, and only when it was satisfied did it propose to the Ministry of the
 vironment that the initial environmental authorizations requested
ould be issued, which they were to CMB on 9 October 2003 and to
 tnia on 14 February 2005.
 Uruguay maintains that it was not required to transmit the environ-
ental impact assessments to Argentina before issuing the initial environ-
ental authorizations to the companies, these authorizations having
en adopted on the basis of its legislation on the subject.
 118. Argentina, for its part, first points out that the environmental
 pact assessments transmitted to it by Uruguay were incomplete, par-
 ularly in that they made no provision for alternative sites for the mills
 d failed to include any consultation of the affected populations. The
ourt will return later in the Judgment to the substantive conditions
hich must be met by environmental impact assessments (see para-
aphs 203 to 219).
 Furthermore, in procedural terms, Argentina considers that the initial
vironmental authorizations should not have been granted to the com-
 nies before it had received the complete environmental impact assess-
ents, and that it was unable to exercise its rights in this context under
 ticles 7 to 11 of the 1975 Statute.
 119. The Court notes that the environmental impact assessments which
e necessary to reach a decision on any plan that is liable to cause sig-

                                                                       49

ficant transboundary harm to another State must be notified by the
 rty concerned to the other party, through CARU, pursuant to Arti-
  7, second and third paragraphs, of the 1975 Statute. This notification
 intended to enable the notified party to participate in the process of
 suring that the assessment is complete, so that it can then consider the
an and its effects with a full knowledge of the facts (Article 8 of the
 75 Statute).
 120. The Court observes that this notification must take place before
e State concerned decides on the environmental viability of the plan,
king due account of the environmental impact assessment submitted to

121. In the present case, the Court observes that the notification to
 gentina of the environmental impact assessments for the CMB (ENCE)
d Orion (Botnia) mills did not take place through CARU, and that
 uguay only transmitted those assessments to Argentina after having
ued the initial environmental authorizations for the two mills in
estion. Thus in the case of CMB (ENCE), the matter was notified to
 gentina on 27 October and 7 November 2003, whereas the initial
vironmental authorization had already been issued on 9 October 2003.
  the case of Orion (Botnia), the file was transmitted to Argentina
tween August 2005 and January 2006, whereas the initial environmental
thorization had been granted on 14 February 2005. Uruguay ought
t, prior to notification, to have issued the initial environmental auth-
 zations and the authorizations for construction on the basis of the envi-
nmental impact assessments submitted to DINAMA. Indeed by doing
   Uruguay gave priority to its own legislation over its procedural
ligations under the 1975 Statute and disregarded the well-established
stomary rule reflected in Article 27 of the Vienna Convention on the
 w of Treaties, according to which “[a] party may not invoke the pro-
 ions of its internal law as justification for its failure to perform a
 aty”.

122. The Court concludes from the above that Uruguay failed to
mply with its obligation to notify the plans to Argentina through
ARU under Article 7, second and third paragraphs, of the 1975
atute.

 C. Whether the Parties Agreed to Derogate from the Procedural
            Obligations Set Out in the 1975 Statute
123. Having thus examined the procedural obligations laid down by
e 1975 Statute, the Court now turns to the question of whether the
 rties agreed, by mutual consent, to derogate from them, as alleged by
 uguay.
124. In this respect the Parties refer to two “agreements” reached on
March 2004 and 5 May 2005 ; however, they hold divergent views
garding their scope and content.

                                                                       50

 The “understanding” of 2 March 2004 between Argentina and
 Uruguay

125. The Court recalls that, after the issuing of the initial environmen-
 authorization to CMB by Uruguay, without CARU having been able
 carry out the functions assigned to it in this context by the 1975 Stat-
e, the Foreign Ministers of the Parties agreed on 2 March 2004 on the
ocedure to be followed, as described in the minutes of the extraordi-
ry meeting of CARU of 15 May 2004. The relevant extract from those
nutes reads as follows in Spanish :

    “II) En fecha 2 de marzo de 2004 los Cancilleres de Argentina y
  Uruguay llegaron a un entendimiento con relación al curso de
  acción que se dará al tema, esto es, facilitar por parte del gobierno
  uruguayo, la información relativa a la construcción de la planta y,
  en relación a la fase operativa, proceder a realizar el monitoreo, por
  parte de CARU, de la calidad de las aguas conforme a su Estatuto.
  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
     I) Ambas delegaciones reafirmaron el compromiso de los Minis-
  tros de Relaciones Exteriores de la República Argentina y de la
  República Oriental del Uruguay de fecha 2 de marzo de 2004 por el
  cual el Uruguay comunicará la información relativa a la construc-
  ción de la planta incluyendo el Plan de Gestión Ambiental. En tal
  sentido, la CARU recibirá los Planes de Gestión Ambiental para la
  construcción y operación de la planta que presente la empresa al
  gobierno uruguayo una vez que le sean remitidos por la delegación
  uruguaya.” (Emphasis in the original.)
Argentina and Uruguay have provided the Court, respectively, with
ench and English translations of these minutes. In view of the discrep-
cies between those two translations, the Court will use the following
nslation :
     “(II) On 2 March 2004, the Foreign Ministers of Argentina and
  Uruguay reached an understanding on how to proceed in the matter,
  namely, that the Uruguayan Government would provide informa-
  tion on the construction of the mill and that, in terms of the opera-
  tional phase, CARU would carry out monitoring of water quality in
  accordance with its Statute.
  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    (I) Both delegations reaffirmed the arrangement which had been
  come to by the Foreign Ministers of the Republic of Argentina and
  the Eastern Republic of Uruguay on 2 March 2004, whereby Uru-
  guay would communicate information on the construction of the
  mill, including the environmental management plan. As a result,
  CARU would receive the environmental management plans for the

                                                                      51

   construction and operation of the mill provided by the company to
   the Uruguayan Government, when these were forwarded to it by the
   Uruguayan delegation.” (Emphasis in the original.) [Translation by
   the Court.]

 126. Uruguay considers that, under the terms of this “understanding”,
e Parties agreed on the approach to be followed in respect of the CMB
 NCE) project, outside CARU, and that there was no reason in law or
gic to prevent them derogating from the procedures outlined in the
 75 Statute pursuant to an appropriate bilateral agreement.
 The said “understanding”, according to Uruguay, only covered the
  nsmission to CARU of the Environmental Management Plans for the
 nstruction and operation of the (CMB) ENCE mill. It supposedly
ereby puts an end to any dispute with Argentina regarding the proce-
 re laid down in Article 7 of the 1975 Statute. Lastly, Uruguay main-
 ns that the “understanding” of 2 March 2004 on the (CMB) ENCE
oject was later extended to include the Orion (Botnia) project, since the
ROCEL water quality monitoring plan put in place by CARU’s Sub-
 mmittee on Water Quality to implement that “understanding” related
  the activity of “both plants”, the CMB (ENCE) and Orion (Botnia)
 lls, the plural having been used in the title and text of the Subcommit-
  ’s report.
 127. Argentina, for its part, maintains that the “understanding”
 tween the two Ministers of 2 March 2004 was intended to ensure com-
 ance with the procedure laid down by the 1975 Statute and thus to
 ntroduce the CMB (ENCE) project within CARU, ending the dispute
   CARU’s jurisdiction to deal with the project. Argentina claims that it
 terated to the organs within CARU that it had not given up its rights
 der Article 7, although it accepted that the dispute between itself and
  uguay in this respect could have been resolved if the procedure con-
mplated in the “understanding” of 2 March 2004 had been brought to
conclusion.
 According to Argentina, however, Uruguay never transmitted the
quired information to CARU as it undertook to do in the “understand-
g” of 2 March 2004. Argentina also denies that the “understanding” of
March 2004 was extended to the Orion (Botnia) mill ; the reference to
 th future plants in the PROCEL plan does not in any way signify, in
  view, the renunciation of the procedure laid down by the 1975 Statute.
 128. The Court first notes that while the existence of the “understand-
g” of 2 March 2004, as minuted by CARU, has not been contested by
e Parties, they differ as to its content and scope. Whatever its specific
 signation and in whatever instrument it may have been recorded (the
ARU minutes), this “understanding” is binding on the Parties, to the
tent that they have consented to it and must be observed by them in
 od faith. They are entitled to depart from the procedures laid down by
e 1975 Statute, in respect of a given project pursuant to an appropriate
 ateral agreement. The Court recalls that the Parties disagree on whether

                                                                      52

e procedure for communicating information provided for by the “under-
 nding” would, if applied, replace that provided for by the 1975 Stat-
e. Be that as it may, such replacement was dependent on Uruguay
mplying with the procedure laid down in the “understanding”.

129. The Court finds that the information which Uruguay agreed to
 nsmit to CARU in the “understanding” of 2 March 2004 was never
 nsmitted. Consequently, the Court cannot accept Uruguay’s conten-
 n that the “understanding” put an end to its dispute with Argentina in
 pect of the CMB (ENCE) mill, concerning implementation of the pro-
dure laid down by Article 7 of the 1975 Statute.

130. Further, the Court observes that, when this “understanding” was
ached, only the CMB (ENCE) project was in question, and that it
erefore cannot be extended to the Orion (Botnia) project, as Uruguay
 ims. The reference to both mills is made only as from July 2004, in the
ntext of the PROCEL plan. However, this plan only concerns the
easures to monitor and control the environmental quality of the river
 ters in the areas of the pulp mills, and not the procedures under Article
of the 1975 Statute.
131. The Court concludes that the “understanding” of 2 March
04 would have had the effect of relieving Uruguay of its obligations
 der Article 7 of the 1975 Statute, if that was the purpose of the “under-
 nding”, only if Uruguay had complied with the terms of the “under-
 nding”. In the view of the Court, it did not do so. Therefore the
nderstanding” cannot be regarded as having had the effect of exempting
 uguay from compliance with the procedural obligations laid down by
e 1975 Statute.

 The agreement setting up the High-Level Technical Group (the
 GTAN)
132. The Court notes that, in furtherance of the agreement reached on
May 2005 between the Presidents of Argentina and Uruguay (see para-
aph 40 above), the Foreign Ministries of the two States issued a press
 ease on 31 May 2005 announcing the creation of the High-Level Tech-
cal Group, referred to by the Parties as the GTAN. According to this
mmuniqué :
     “In conformity with what was agreed to by the Presidents of
  Argentina and Uruguay, the Foreign Ministries of both of our
  countries constitute, under their supervision, a Group of Techni-
  cal Experts for complementary studies and analysis, exchange of
  information and follow-up on the effects that the operation of the
  cellulose plants that are being constructed in the Eastern Republic
  of Uruguay will have on the ecosystem of the shared Uruguay
  River.

                                                                       53

     This Group . . . is to produce an initial report within a period of
   180 days.”

 133. Uruguay regards this press release as an agreement that binds the
 o States, whereby they decided to make the GTAN the body within
hich the direct negotiations between the Parties provided for by
 ticle 12 of the 1975 Statute would take place, since its purpose was to
 alyse the effects on the environment of the “operation of the cellu-
 e plants that are being constructed in the Eastern Republic of Uruguay”.
 uguay infers from this that the Parties were agreed on the construction
 the mills and that they had limited the extent of the dispute between
em to the environmental risks caused by their operation. Uruguay sees
oof of this in the referral to the Court on the basis of Article 12 of the
 75 Statute, which allows either Party to apply to the Court in the event
 the negotiations failing to produce an agreement within the period of
 0 days.
 According to Uruguay, therefore, the agreement contained in the press
 ease of 31 May 2005, by paving the way for the direct negotiations
ovided for in Article 12, covered any possible procedural irregularities
 relation to Articles 7 et seq. of the 1975 Statute. Uruguay points out
at it communicated all the necessary information to Argentina during
e 12 meetings held by the GTAN and that it transmitted the Orion
 otnia) port project to CARU, as agreed by the Parties at the first meet-
g of the GTAN.
 134. Uruguay further notes that the 1975 Statute is silent as to whether
e notifying State may or may not implement a project while negotia-
 ns are ongoing. It acknowledges that, under international law, the ini-
 ting State must refrain from doing so during the period of negotiation,
 t takes the view that this does not apply to all work and, in particular,
at preparatory work is permitted. Uruguay acknowledges that it car-
 d out such work, for example construction of the foundations for the
 ion (Botnia) mill, but in its view this did not involve faits accomplis
hich prevented the negotiations from reaching a conclusion. Uruguay
 o considers that it had no legal obligation to suspend any and all work
  the port.

135. Argentina considers that no acceptance on its part of the con-
 uction of the disputed mills can be inferred from the terms of the press
ease of 31 May 2005. It submits that in creating the GTAN, the Parties
d not decide to substitute it for CARU, but regarded it as a means of
gotiation that would co-exist with the latter.

Contrary to Uruguay, Argentina takes the view that this matter has
en submitted to the Court on the basis of Article 60 of the 1975 Statute
d not of Article 12, since Uruguay, by its conduct, has prevented the
ter from being used as a basis, having allegedly disregarded the entire
ocedure laid down in Chapter II of the Statute. Argentina therefore

                                                                       54

es it as for the Court to pronounce on all the breaches of the 1975 Stat-
e, including and not limited to the authorization for the construction of
e disputed mills.
136. Argentina submits that Uruguay, by its conduct, frustrated the
ocedures laid down in Articles 7 to 9 of the 1975 Statute and that, dur-
g the period of negotiation within the GTAN, Uruguay continued the
nstruction work on the Orion (Botnia) mill and began building the
 rt terminal. During that same period, Argentina reiterated, within
ARU, the need for Uruguay to comply with its procedural obligations
 der Articles 7 to 12 of the 1975 Statute and to suspend the works.

Lastly, Argentina rejects Uruguay’s claim that the work on the foun-
tions of the Orion (Botnia) mill, its chimney and the port was merely
eliminary in nature and cannot be regarded as the beginning of con-
uction work as such. For Argentina, such a distinction is groundless
d cannot be justified by the nature of the work carried out.

 137. The Court first points out that there is no reason to distinguish,
  Uruguay and Argentina have both done for the purpose of their
 pective cases, between referral on the basis of Article 12 and of Arti-
  60 of the 1975 Statute. While it is true that Article 12 provides for
course to the procedure indicated in Chapter XV, should the negotia-
 ns fail to produce an agreement within the 180-day period, its purpose
ds there. Article 60 then takes over, in particular its first paragraph,
hich enables either Party to submit to the Court any dispute concerning
e interpretation or application of the Statute which cannot be settled by
 ect negotiations. This wording also covers a dispute relating to the
 erpretation or application of Article 12, like any other provision of the
 75 Statute.

138. The Court notes that the press release of 31 May 2005 sets out an
reement between the two States to create a negotiating framework, the
TAN, in order to study, analyse and exchange information on the
 ects that the operation of the cellulose plants that were being con-
 ucted in the Eastern Republic of Uruguay could have on the ecosystem
 the shared Uruguay River, with “the group [having] to produce an ini-
 l report within a period of 180 days”.
139. The Court recognizes that the GTAN was created with the aim of
abling the negotiations provided for in Article 12 of the 1975 Statute,
 o for a 180-day period, to take place. Under Article 11, these negotia-
 ns between the parties with a view to reaching an agreement are to be
ld once the notified party has sent a communication to the other party,
rough the Commission, specifying

   “which aspects of the work or the programme of operations might
   significantly impair navigation, the régime of the river or the quality

                                                                       55

   of its waters, the technical reasons on which this conclusion is based
   and the changes suggested to the plan or programme of opera-
   tions”.

The Court is aware that the negotiation provided for in Article 12 of
e 1975 Statute forms part of the overall procedure laid down in Articles
 o 12, which is structured in such a way that the parties, in association
th CARU, are able, at the end of the process, to fulfil their obligation
 prevent any significant transboundary harm which might be caused by
 tentially harmful activities planned by either one of them.

 140. The Court therefore considers that the agreement to set up the
TAN, while indeed creating a negotiating body capable of enabling
e Parties to pursue the same objective as that laid down in Article 12
 the 1975 Statute, cannot be interpreted as expressing the agreement of
e Parties to derogate from other procedural obligations laid down by
e Statute.
 141. Consequently, the Court finds that Argentina, in accepting the
eation of the GTAN, did not give up, as Uruguay claims, the other
ocedural rights belonging to it by virtue of the 1975 Statute, nor the
 ssibility of invoking Uruguay’s responsibility for any breach of those
 hts. Argentina did not, in the agreement to set up the GTAN, “effect
 clear and unequivocal waiver” of its rights under the 1975 Statute
 ertain Phosphate Lands in Nauru (Nauru v. Australia), Preliminary
bjections, Judgment, I.C.J. Reports 1992, p. 247, para. 13). Nor did it
nsent to suspending the operation of the procedural provisions of the
 75 Statute. Indeed, under Article 57 of the Vienna Convention on the
 w of Treaties of 23 May 1969, concerning “[s]uspension of the opera-
 n of a treaty”, including, according to the International Law Commis-
 n’s commentary, suspension of “the operation of . . . some of its
ovisions” (Yearbook of the International Law Commission, 1966,
ol. II, p. 251), suspension is only possible “in conformity with the pro-
 ions of the treaty” or “by consent of all the parties”.
 142. The Court further observes that the agreement to set up the
TAN, in referring to “the cellulose plants that are being constructed in
e Eastern Republic of Uruguay”, is stating a simple fact and cannot be
 erpreted, as Uruguay claims, as an acceptance of their construction by
 gentina.
 143. The Court finds that Uruguay was not entitled, for the duration
 the period of consultation and negotiation provided for in Articles 7 to
  of the 1975 Statute, either to construct or to authorize the construc-
 n of the planned mills and the port terminal. It would be contrary to
e object and purpose of the 1975 Statute to embark on disputed activi-
 s before having applied the procedures laid down by the “joint machin-
y necessary for the optimum and rational utilization of the [r]iver”
 rticle 1). However, Article 9 provides that : “[i]f the notified party raises
  objections or does not respond within the period established in Arti-

                                                                           56

   8 [180 days], the other party may carry out or authorize the work
anned”.
 144. Consequently, in the opinion of the Court, as long as the proce-
 ral mechanism for co-operation between the parties to prevent signifi-
nt damage to one of them is taking its course, the State initiating the
anned activity is obliged not to authorize such work and, a fortiori, not
  carry it out.
 145. The Court notes, moreover, that the 1975 Statute is perfectly in
 eping with the requirements of international law on the subject, since
e mechanism for co-operation between States is governed by the prin-
ple of good faith. Indeed, according to customary international law, as
flected in Article 26 of the 1969 Vienna Convention on the Law of
 eaties, “[e]very treaty in force is binding upon the parties to it and must
   performed by them in good faith”. That applies to all obligations
 ablished by a treaty, including procedural obligations which are essen-
 l to co-operation between States. The Court recalled in the cases con-
rning Nuclear Tests (Australia v. France) (New Zealand v. France):
     “One of the basic principles governing the creation and perform-
   ance of legal obligations, whatever their source, is the principle of
   good faith. Trust and confidence are inherent in international
   co-operation . . .” (Judgments, I.C.J. Reports 1974, p. 268, para. 46,
   and p. 473, para. 49 ; see also Border and Transborder Armed Actions
   (Nicaragua v. Honduras), Jurisdiction and Admissibility, Judgment,
   I.C.J. Reports 1988, p. 105, para. 94.)
 146. The Court has also had occasion to draw attention to the charac-
 istics of the obligation to negotiate and to the conduct which this
 poses on the States concerned : “[the Parties] are under an obligation
  to conduct themselves that the negotiations are meaningful” (North
 a Continental Shelf (Federal Republic of Germany/Denmark ; Federal
 public of Germany/Netherlands), Judgment, I.C.J. Reports 1969, p. 47,
 ra. 85).
 147. In the view of the Court, there would be no point to the co-opera-
 n mechanism provided for by Articles 7 to 12 of the 1975 Statute if the
 rty initiating the planned activity were to authorize or implement it
thout waiting for that mechanism to be brought to a conclusion.
deed, if that were the case, the negotiations between the parties would
  longer have any purpose.
 148. In this respect, contrary to what Uruguay claims, the preliminary
ork on the pulp mills on sites approved by Uruguay alone does not con-
tute an exception. This work does in fact form an integral part of the
nstruction of the planned mills (see paragraphs 39 and 42 above).

149. The Court concludes from the above that the agreement to set up
e GTAN did not permit Uruguay to derogate from its obligations of
 ormation and notification under Article 7 of the 1975 Statute, and that
  authorizing the construction of the mills and the port terminal at

                                                                         57

 ay Bentos before the expiration of the period of negotiation, Uruguay
 led to comply with the obligation to negotiate laid down by Article 12
  the Statute. Consequently, Uruguay disregarded the whole of the
-operation mechanism provided for in Articles 7 to 12 of the 1975 Statute.
150. Given that “an obligation to negotiate does not imply an obliga-
 n to reach an agreement” (Railway Traffic between Lithuania and
 land, Advisory Opinion, 1931, P.C.I.J., Series A/B, No. 42, p. 116), it
mains for the Court to examine whether the State initiating the plan is
 der certain obligations following the end of the negotiation period pro-
ded for in Article 12.

            D. Uruguay’s Obligations Following the End
                    of the Negotiation Period
151. Article 12 refers the Parties, should they fail to reach an agree-
ent within 180 days, to the procedure indicated in Chapter XV.

Chapter XV contains a single article, Article 60, according to which :
      “Any dispute concerning the interpretation or application of the
   Treaty and the Statute which cannot be settled by direct negotiations
   may be submitted by either party to the International Court of Jus-
   tice.
      In the cases referred to in Articles 58 and 59, either party may sub-
   mit any dispute concerning the interpretation or application of the
   Treaty and the Statute to the International Court of Justice, when it
   has not been possible to settle the dispute within 180 days following
   the notification referred to in Article 59.”
152. According to Uruguay, the 1975 Statute does not give one party
“right of veto” over the projects initiated by the other. It does not con-
 er there to be a “no construction obligation” borne by the State initi-
 ng the projects until such time as the Court has ruled on the dispute.
 uguay points out that the existence of such an obligation would enable
 e party to block a project that was essential for the sustainable devel-
 ment of the other, something that would be incompatible with the
 ptimum and rational utilization of the [r]iver”. On the contrary, for
 uguay, in the absence of any specific provision in the 1975 Statute, ref-
ence should be made to general international law, as reflected in the
01 draft Articles of the International Law Commission on Prevention
  Transboundary Harm from Hazardous Activities (Yearbook of the
 ernational Law Commission, 2001, Vol. II, Part Two) ; in particular,
aft Article 9, paragraph 3, concerning “Consultations on preventive
easures”, states that “[i]f the consultations . . . fail to produce an agreed
 ution, the State of origin shall nevertheless take into account the inter-
 s of the State likely to be affected in case it decides to authorize the
tivity to be pursued . . .”.

                                                                          58

 153. Argentina, on the other hand, maintains that Article 12 of the
 75 Statute makes the Court the final decision-maker where the parties
 ve failed to reach agreement within 180 days following the notification
 erred to in Article 11. It is said to follow from Article 9 of the Statute,
 erpreted in the light of Articles 11 and 12 and taking account of its
 ject and purpose, that if the notified party raises an objection, the
her party may neither carry out nor authorize the work in question
 til the procedure laid down in Articles 7 to 12 has been completed and
e Court has ruled on the project. Argentina therefore considers that,
 ring the dispute settlement proceedings before the Court, the State
hich is envisaging carrying out the work cannot confront the other
 rty with the fait accompli of having carried it out.

 Argentina argues that the question of the “veto” raised by Uruguay is
appropriate, since neither of the parties can impose its position in
 pect of the construction works and it will ultimately be for the Court
  settle the dispute, if the parties disagree, by a decision that will have
e force of res judicata. It could be said, according to Argentina, that
 uguay has no choice but to come to an agreement with it or to await
e settlement of the dispute. Argentina contends that, by pursuing the
nstruction and commissioning of the Orion (Botnia) mill and port,
 uguay has committed a continuing violation of the procedural obliga-
 ns under Chapter II of the 1975 Statute.
 154. The Court observes that the “no construction obligation”, said to
  borne by Uruguay between the end of the negotiation period and the
cision of the Court, is not expressly laid down by the 1975 Statute and
 es not follow from its provisions. Article 9 only provides for such an
 ligation during the performance of the procedure laid down in Arti-
 s 7 to 12 of the Statute.
 Furthermore, in the event of disagreement between the parties on the
anned activity persisting at the end of the negotiation period, the Stat-
e does not provide for the Court, to which the matter would be sub-
 tted by the State concerned, according to Argentina, to decide whether
  not to authorize the activity in question. The Court points out that,
hile the 1975 Statute gives it jurisdiction to settle any dispute concern-
g its interpretation or application, it does not however confer on it the
 e of deciding in the last resort whether or not to authorize the planned
tivities. Consequently, the State initiating the plan may, at the end of
e negotiation period, proceed with construction at its own risk.
 The Court cannot uphold the interpretation of Article 9 according to
hich any construction is prohibited until the Court has given its ruling
 rsuant to Articles 12 and 60.
 155. Article 12 does not impose an obligation on the parties to submit
matter to the Court, but gives them the possibility of doing so, follow-
g the end of the negotiation period. Consequently, Article 12 can do
 thing to alter the rights and obligations of the party concerned as long
  the Court has not ruled finally on them. The Court considers that

                                                                         59

ose rights include that of implementing the project, on the sole respon-
 ility of that party, since the period for negotiation has expired.
156. In its Order of 13 July 2006, the Court took the view that the
onstruction [of the mills] at the current site cannot be deemed to create
 ait accompli” (Pulp Mills on the River Uruguay (Argentina v. Uru-
ay), Provisional Measures, Order of 13 July 2006, I.C.J. Reports 2006,
  133, para. 78). Thus, in pronouncing on the merits in the dispute
tween the Parties, the Court is the ultimate guarantor of their compli-
 ce with the 1975 Statute.
157. The Court concludes from the above that Uruguay did not bear
 y “no construction obligation” after the negotiation period provided
r in Article 12 expired on 3 February 2006, the Parties having deter-
 ned at that date that the negotiations undertaken within the GTAN
 d failed (see paragraph 40). Consequently the wrongful conduct of
 uguay (established in paragraph 149 above) could not extend beyond
at period.
158. Having established that Uruguay breached its procedural obliga-
 ns to inform, notify and negotiate to the extent and for the reasons
ven above, the Court will now turn to the question of the compliance of
at State with the substantive obligations laid down by the 1975 Statute.

                                 * *

                    IV. SUBSTANTIVE OBLIGATIONS

159. Before taking up the examination of the alleged violations of
bstantive obligations under the 1975 Statute, the Court will address
o preliminary issues, namely, the burden of proof and expert
dence.

              A. Burden of Proof and Expert Evidence
160. Argentina contends that the 1975 Statute adopts an approach in
 ms of precaution whereby “the burden of proof will be placed on Uru-
ay for it to establish that the Orion (Botnia) mill will not cause signifi-
nt damage to the environment”. It also argues that the burden of proof
ould not be placed on Argentina alone as the Applicant, because, in its
 w, the 1975 Statute imposes an equal onus to persuade — for the one
at the plant is innocuous and for the other that it is harmful.

 161. Uruguay, on the other hand, asserts that the burden of proof is
  Argentina, as the Applicant, in accordance with the Court’s long-
 nding case law, although it considers that, even if the Argentine posi-
 n about transferring the burden of proof to Uruguay were correct, it
ould make no difference given the manifest weakness of Argentina’s

                                                                        60

 se and the extensive independent evidence put before the Court by
  uguay. Uruguay also strongly contests Argentina’s argument that the
 ecautionary approach of the 1975 Statute would imply a reversal of the
 rden of proof, in the absence of an explicit treaty provision prescribing
 as well as Argentina’s proposition that the Statute places the burden of
 oof equally on both Parties.

 162. To begin with, the Court considers that, in accordance with the
  ll-established principle of onus probandi incumbit actori, it is the duty
  the party which asserts certain facts to establish the existence of such
cts. This principle which has been consistently upheld by the Court
Maritime Delimitation in the Black Sea (Romania v. Ukraine), Judg-
  nt, I.C.J. Reports 2009, p. 86, para. 68 ; Sovereignty over Pedra
 anca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia/
 ngapore), Judgment, I.C.J. Reports 2008, p. 31, para. 45 ; Application
   the Convention on the Prevention and Punishment of the Crime of
  nocide (Bosnia and Herzegovina v. Serbia and Montenegro), Judgment,
C.J. Reports 2007 (I), p. 128, para. 204 ; Military and Paramilitary
  tivities in and against Nicaragua (Nicaragua v. United States of
merica), Jurisdiction and Admissibility, Judgment, I.C.J. Reports 1984,
  437, para. 101) applies to the assertions of fact both by the Applicant
 d the Respondent.
 163. It is of course to be expected that the Applicant should, in the
 st instance, submit the relevant evidence to substantiate its claims. This
  es not, however, mean that the Respondent should not co-operate in
 e provision of such evidence as may be in its possession that could assist
 e Court in resolving the dispute submitted to it.
 164. Regarding the arguments put forward by Argentina on the
versal of the burden of proof and on the existence, vis-à-vis each Party,
  an equal onus to prove under the 1975 Statute, the Court considers
 at while a precautionary approach may be relevant in the interpretation
 d application of the provisions of the Statute, it does not follow that it
  erates as a reversal of the burden of proof. The Court is also of the
  w that there is nothing in the 1975 Statute itself to indicate that it
aces the burden of proof equally on both Parties.

                                    *
 165. The Court now turns to the issue of expert evidence. Both
 gentina and Uruguay have placed before the Court a vast amount
 factual and scientific material in support of their respective claims.
hey have also submitted reports and studies prepared by the experts
 d consultants commissioned by each of them, as well as others
 mmissioned by the International Finance Corporation in its quality
  lender to the project. Some of these experts have also appeared

                                                                        61

 fore the Court as counsel for one or the other of the Parties to pro-
de evidence.
 166. The Parties, however, disagree on the authority and reliability of
e studies and reports submitted as part of the record and prepared, on
e one hand, by their respective experts and consultants, and on the
her, by the experts of the IFC, which contain, in many instances, con-
cting claims and conclusions. In reply to a question put by a judge,
 gentina stated that the weight to be given to such documents should be
termined by reference not only to the “independence” of the author,
ho must have no personal interest in the outcome of the dispute and
ust not be an employee of the government, but also by reference to the
aracteristics of the report itself, in particular the care with which its
 alysis was conducted, its completeness, the accuracy of the data used,
 d the clarity and coherence of the conclusions drawn from such data.
  its reply to the same question, Uruguay suggested that reports
epared by retained experts for the purposes of the proceedings
 d submitted as part of the record should not be regarded as
dependent and should be treated with caution ; while expert statements
 d evaluations issued by a competent international organization, such
  the IFC, or those issued by the consultants engaged by that
ganization should be regarded as independent and given “special weight”.

 167. The Court has given most careful attention to the material sub-
 tted to it by the Parties, as will be shown in its consideration of the
 dence below with respect to alleged violations of substantive obliga-
 ns. Regarding those experts who appeared before it as counsel at the
arings, the Court would have found it more useful had they been pre-
nted by the Parties as expert witnesses under Articles 57 and 64 of the
ules of Court, instead of being included as counsel in their respective
legations. The Court indeed considers that those persons who provide
 dence before the Court based on their scientific or technical knowledge
 d on their personal experience should testify before the Court as
perts, witnesses or in some cases in both capacities, rather than coun-
 , so that they may be submitted to questioning by the other party as
 ll as by the Court.
 168. As for the independence of such experts, the Court does not find
necessary in order to adjudicate the present case to enter into a general
 cussion on the relative merits, reliability and authority of the docu-
ents and studies prepared by the experts and consultants of the Parties.
 needs only to be mindful of the fact that, despite the volume and com-
exity of the factual information submitted to it, it is the responsibility
 the Court, after having given careful consideration to all the evidence
aced before it by the Parties, to determine which facts must be consid-
ed relevant, to assess their probative value, and to draw conclusions
om them as appropriate. Thus, in keeping with its practice, the Court
ll make its own determination of the facts, on the basis of the evidence

                                                                       62

esented to it, and then it will apply the relevant rules of international
w to those facts which it has found to have existed.

          B. Alleged Violations of Substantive Obligations
169. The Court now turns to the examination of the alleged violations
  Uruguay of its substantive obligations under the 1975 Statute by
thorizing the construction and operation of the Orion (Botnia) mill. In
rticular, Argentina contends that Uruguay has breached its obligations
der Articles 1, 27, 35, 36 and 41 (a) of the 1975 Statute and “other
ligations deriving from . . . general, conventional and customary inter-
tional law which are necessary for the application of the 1975 Statute”.
uguay rejects these allegations. Uruguay considers furthermore that
ticle 27 of the 1975 Statute allows the parties to use the waters of the
er for domestic, sanitary, industrial and agricultural purposes.

 The obligation to contribute to the optimum and rational utilization
 of the river (Article 1)
170. According to Argentina, Uruguay has breached its obligation to
ntribute to the “optimum and rational utilization of the river” by fail-
g to co-ordinate with Argentina on measures necessary to avoid eco-
gical change, and by failing to take the measures necessary to prevent
 llution. Argentina also maintains that, in interpreting the 1975 Statute
  particular Articles 27, 35, and 36 thereof) according to the principle of
uitable and reasonable use, account must be taken of all pre-existing
 itimate uses of the river, including in particular its use for recreational
d tourist purposes.
171. For Uruguay, the object and purpose of the 1975 Statute is to
 ablish a structure for co-operation between the Parties through CARU
 pursuit of the shared goal of equitable and sustainable use of the water
d biological resources of the river. Uruguay contends that it has in no
 y breached the principle of equitable and reasonable use of the river
d that this principle provides no basis for favouring pre-existing uses of
e river, such as tourism or fishing, over other, new uses.

172. The Parties also disagree on the scope and implications of Arti-
  27 of the 1975 Statute on the right of each Party to use the waters of
e river, within its jurisdiction, for domestic, sanitary, industrial and
ricultural purposes.
173. The Court observes that Article 1, as stated in the title to Chap-
  I of the 1975 Statute, sets out the purpose of the Statute. As such, it
 orms the interpretation of the substantive obligations, but does not by
elf lay down specific rights and obligations for the parties. Optimum
d rational utilization is to be achieved through compliance with the
 ligations prescribed by the 1975 Statute for the protection of the envi-

                                                                         63

nment and the joint management of this shared resource. This objec-
 e must also be ensured through CARU, which constitutes “the joint
achinery” necessary for its achievement, and through the regulations
opted by it as well as the regulations and measures adopted by the
 rties.

174. The Court recalls that the Parties concluded the treaty embody-
g the 1975 Statute, in implementation of Article 7 of the 1961 Treaty,
quiring the Parties jointly to establish a régime for the use of the river
vering, inter alia, provisions for preventing pollution and protecting
 d preserving the aquatic environment. Thus, optimum and rational uti-
ation may be viewed as the cornerstone of the system of co-operation
 ablished in the 1975 Statute and the joint machinery set up to imple-
ent this co-operation.
175. The Court considers that the attainment of optimum and rational
 lization requires a balance between the Parties’ rights and needs to use
e river for economic and commercial activities on the one hand, and
e obligation to protect it from any damage to the environment that
ay be caused by such activities, on the other. The need for this balance
 reflected in various provisions of the 1975 Statute establishing rights
 d obligations for the Parties, such as Articles 27, 36, and 41. The Court
ll therefore assess the conduct of Uruguay in authorizing the construc-
 n and operation of the Orion (Botnia) mill in the light of those provi-
 ns of the 1975 Statute, and the rights and obligations prescribed
erein.
176. The Court has already addressed in paragraphs 84 to 93 above
e role of CARU with respect to the procedural obligations laid down in
e 1975 Statute. In addition to its role in that context, the functions of
ARU relate to almost all aspects of the implementation of the substan-
 e provisions of the 1975 Statute. Of particular relevance in the present
se are its functions relating to rule-making in respect of conservation
 d preservation of living resources, the prevention of pollution and its
onitoring, and the co-ordination of actions of the Parties. These func-
 ns will be examined by the Court in its analysis of the positions of the
 rties with respect to the interpretation and application of Articles 36
 d 41 of the 1975 Statute.

177. Regarding Article 27, it is the view of the Court that its formula-
 n reflects not only the need to reconcile the varied interests of riparian
ates in a transboundary context and in particular in the use of a shared
tural resource, but also the need to strike a balance between the use of
e waters and the protection of the river consistent with the objective of
stainable development. The Court has already dealt with the obliga-
 ns arising from Articles 7 to 12 of the 1975 Statute which have to be
 served, according to Article 27, by any party wishing to exercise its
 ht to use the waters of the river for any of the purposes mentioned
erein insofar as such use may be liable to affect the régime of the river

                                                                        64

 the quality of its waters. The Court wishes to add that such utilization
uld not be considered to be equitable and reasonable if the interests of
e other riparian State in the shared resource and the environmental
otection of the latter were not taken into account. Consequently, it is
e opinion of the Court that Article 27 embodies this interconnectedness
tween equitable and reasonable utilization of a shared resource and the
lance between economic development and environmental protection
at is the essence of sustainable development.

 The obligation to ensure that the management of the soil and wood-
 land does not impair the régime of the river or the quality of its waters
 (Article 35)
178. Article 35 of the 1975 Statute provides that the parties :
   “undertake to adopt the necessary measures to ensure that the man-
   agement of the soil and woodland and the use of groundwater and
   the waters of the tributaries of the river do not cause changes which
   may significantly impair the régime of the river or the quality of its
   waters”.
 179. Argentina contends that Uruguay’s decision to carry out major
calyptus planting operations to supply the raw material for the Orion
 otnia) mill has an impact on management of the soil and Uruguayan
oodland, but also on the quality of the waters of the river. For its part,
 uguay states that Argentina does not make any arguments that are
 sed on Uruguay’s management of soil or woodland — “nor has it
ade any allegations concerning the waters of tributaries”.

180. The Court observes that Argentina has not provided any evidence
 support its contention. Moreover, Article 35 concerns the management
 the soil and woodland as well as the use of groundwater and the water
 tributaries, and there is nothing to suggest, in the evidentiary material
bmitted by Argentina, a direct relationship between Uruguay’s man-
ement of the soil and woodland, or its use of ground water and water
 tributaries and the alleged changes in the quality of the waters of the
ver Uruguay which had been attributed by Argentina to the Orion
otnia) mill. Indeed, while Argentina made lengthy arguments about the
ects of the pulp mill discharges on the quality of the waters of the river,
  similar arguments have been presented to the Court regarding a del-
 rious relationship between the quality of the waters of the river and
e eucalyptus-planting operations by Uruguay. The Court concludes
at Argentina has not established its contention on this matter.

 The obligation to co-ordinate measures to avoid changes in the ecolo-
 gical balance (Article 36)
181. Argentina contends that Uruguay has breached Article 36 of the

                                                                        65

 75 Statute, which places the Parties under an obligation to co-ordinate
rough CARU the necessary measures to avoid changing the ecological
 lance of the river. Argentina asserts that the discharges from the Orion
 otnia) mill altered the ecological balance of the river, and cites as
amples the 4 February 2009 algal bloom, which, according to it, pro-
des graphic evidence of a change in the ecological balance, as well as
e discharge of toxins, which gave rise, in its view, to the malformed
tifers whose pictures were shown to the Court.
 182. Uruguay considers that any assessment of the Parties’ conduct in
 ation to Article 36 of the 1975 Statute must take account of the rules
 opted by CARU, because this Article, creating an obligation of co-op-
ation, refers to such rules and does not by itself prohibit any specific
 nduct. Uruguay takes the position that the mill fully meets CARU
quirements concerning the ecological balance of the river, and con-
udes that it has not acted in breach of Article 36 of the 1975 Statute.

 183. It is recalled that Article 36 provides that “[t]he parties shall co-
dinate, through the Commission, the necessary measures to avoid any
ange in the ecological balance and to control pests and other harmful
ctors in the river and the areas affected by it”.
 184. It is the opinion of the Court that compliance with this obligation
nnot be expected to come through the individual action of either Party,
ting on its own. Its implementation requires co-ordination through the
ommission. It reflects the common interest dimension of the 1975 Stat-
e and expresses one of the purposes for the establishment of the joint
achinery which is to co-ordinate the actions and measures taken by the
 rties for the sustainable management and environmental protection of
e river. The Parties have indeed adopted such measures through the
omulgation of standards by CARU. These standards are to be found in
ctions E3 and E4 of the CARU Digest. One of the purposes of Sec-
 n E3 is “[t]o protect and preserve the water and its ecological balance”.
milarly, it is stated in Section E4 that the section was developed “in
cordance with . . . Articles 36, 37, 38, and 39”.

185. In the view of the Court, the purpose of Article 36 of the 1975
atute is to prevent any transboundary pollution liable to change the
ological balance of the river by co-ordinating, through CARU, the
 option of the necessary measures. It thus imposes an obligation on
 th States to take positive steps to avoid changes in the ecological
 lance. These steps consist not only in the adoption of a regulatory
  mework, as has been done by the Parties through CARU, but
 o in the observance as well as enforcement by both Parties of
e measures adopted. As the Court emphasized in the Gabčíkovo-
agymaros case :

   “in the field of environmental protection, vigilance and prevention
   are required on account of the often irreversible character of damage

                                                                        66

  to the environment and of the limitations inherent in the very
  mechanism of reparation of this type of damage” (Gabčíkovo-
  Nagymaros Project (Hungary/Slovakia), Judgment, I.C.J. Reports
  1997, p. 78, para. 140).
186. The Parties also disagree with respect to the nature of the obliga-
n laid down in Article 36, and in particular whether it is an obligation
 conduct or of result. Argentina submits that, on a plain meaning,
th Articles 36 and 41 of the 1975 Statute establish an obligation
 result.
187. The Court considers that the obligation laid down in Article 36 is
dressed to both Parties and prescribes the specific conduct of co-ordi-
ting the necessary measures through the Commission to avoid changes
the ecological balance. An obligation to adopt regulatory or adminis-
 tive measures either individually or jointly and to enforce them is an
ligation of conduct. Both Parties are therefore called upon, under Arti-
  36, to exercise due diligence in acting through the Commission for the
cessary measures to preserve the ecological balance of the river.

188. This vigilance and prevention is all the more important in the
eservation of the ecological balance, since the negative impact of
man activities on the waters of the river may affect other components
 the ecosystem of the watercourse such as its flora, fauna, and soil. The
ligation to co-ordinate, through the Commission, the adoption of the
cessary measures, as well as their enforcement and observance, assumes,
 this context, a central role in the overall system of protection of the
ver Uruguay established by the 1975 Statute. It is therefore of crucial
portance that the Parties respect this obligation.

189. In light of the above, the Court is of the view that Argentina has
t convincingly demonstrated that Uruguay has refused to engage in
ch co-ordination as envisaged by Article 36, in breach of that provi-
 n.

 The obligation to prevent pollution and preserve the aquatic environ-
 ment (Article 41)

190. Article 41 provides that :
     “Without prejudice to the functions assigned to the Commission
  in this respect, the parties undertake :
  (a) to protect and preserve the aquatic environment and, in par-
       ticular, to prevent its pollution, by prescribing appropriate
       rules and [adopting appropriate] measures in accordance with
       applicable international agreements and in keeping, where rele-

                                                                      67

      vant, with the guidelines and recommendations of international
      technical bodies ;
  (b) not to reduce in their respective legal systems :
      1. the technical requirements in force for preventing water pol-
          lution, and
      2. the severity of the penalties established for violations ;
  (c) to inform one another of any rules which they plan to prescribe
      with regard to water pollution in order to establish equivalent
      rules in their respective legal systems.”
191. Argentina claims that by allowing the discharge of additional
 trients into a river that is eutrophic and suffers from reverse flow and
 gnation, Uruguay violated the obligation to prevent pollution, as it
 led to prescribe appropriate measures in relation to the Orion (Botnia)
 ll, and failed to meet applicable international environmental agree-
ents, including the Biodiversity Convention and the Ramsar Conven-
 n. It maintains that the 1975 Statute prohibits any pollution which is
ejudicial to the protection and preservation of the aquatic environment
  which alters the ecological balance of the river. Argentina further
gues that the obligation to prevent pollution of the river is an obliga-
 n of result and extends not only to protecting the aquatic environment
oper, but also to any reasonable and legitimate use of the river, includ-
g tourism and other recreational uses.

192. Uruguay contends that the obligation laid down in Article 41 (a)
the 1975 Statute to “prevent . . . pollution” does not involve a prohibi-
n on all discharges into the river. It is only those that exceed the stand-
ds jointly agreed by the Parties within CARU in accordance with their
ernational obligations, and that therefore have harmful effects, which
n be characterized as “pollution” under Article 40 of the 1975 Statute.
 uguay also maintains that Article 41 creates an obligation of conduct,
d not of result, but that it actually matters little since Uruguay has
mplied with its duty to prevent pollution by requiring the plant to meet
st available technology (“BAT”) standards.

193. Before turning to the analysis of Article 41, the Court recalls
at :
    “The existence of the general obligation of States to ensure that
  activities within their jurisdiction and control respect the environ-
  ment of other States or of areas beyond national control is now part
  of the corpus of international law relating to the environment.”
  (Legality of the Threat or Use of Nuclear Weapons, Advisory Opin-
  ion, I.C.J. Reports 1996 (I), pp. 241-242, para. 29.)

194. The Court moreover had occasion to stress, in the Gabčíkovo-
agymaros Project case, that “the Parties together should look afresh at

                                                                        68

e effects on the environment of the operation of the Gabčíkovo power
ant” (Gabčíkovo-Nagymaros Project (Hungary/Slovakia), Judgment,
C.J. Reports 1997, p. 78, para. 140). The Court is mindful of these
 tements in taking up now the examination of Article 41 of the
75 Statute.
195. In view of the central role of this provision in the dispute between
e Parties in the present case and their profound differences as to its
 erpretation and application, the Court will make a few remarks of a
neral character on the normative content of Article 41 before address-
g the specific arguments of the Parties. First, in the view of the Court,
 ticle 41 makes a clear distinction between regulatory functions
trusted to CARU under the 1975 Statute, which are dealt with in Arti-
  56 of the Statute, and the obligation it imposes on the Parties to adopt
 es and measures individually to “protect and preserve the aquatic envi-
nment and, in particular, to prevent its pollution”. Thus, the obligation
sumed by the Parties under Article 41, which is distinct from those
 der Articles 36 and 56 of the 1975 Statute, is to adopt appropriate rules
 d measures within the framework of their respective domestic legal
stems to protect and preserve the aquatic environment and to prevent
 llution. This conclusion is supported by the wording of paragraphs (b)
 d (c) of Article 41, which refer to the need not to reduce the technical
quirements and severity of the penalties already in force in the respec-
 e legislation of the Parties as well as the need to inform each other of
e rules to be promulgated so as to establish equivalent rules in their
 al systems.

196. Secondly, it is the opinion of the Court that a simple reading of
e text of Article 41 indicates that it is the rules and measures that are to
  prescribed by the Parties in their respective legal systems which must
  “in accordance with applicable international agreements” and “in
eping, where relevant, with the guidelines and recommendations of
 ernational technical bodies”.
197. Thirdly, the obligation to “preserve the aquatic environment, and
  particular to prevent pollution by prescribing appropriate rules and
easures” is an obligation to act with due diligence in respect of all
tivities which take place under the jurisdiction and control of each
 rty. It is an obligation which entails not only the adoption of appro-
 ate rules and measures, but also a certain level of vigilance in their
forcement and the exercise of administrative control applicable to pub-
  and private operators, such as the monitoring of activities undertaken
   such operators, to safeguard the rights of the other party. The
 ponsibility of a party to the 1975 Statute would therefore be engaged
 it was shown that it had failed to act diligently and thus take all
propriate measures to enforce its relevant regulations on a public or private
 erator under its jurisdiction. The obligation of due diligence
 der Article 41 (a) in the adoption and enforcement of appropriate

                                                                          69

 es and measures is further reinforced by the requirement that such
 es and measures must be “in accordance with applicable international
reements” and “in keeping, where relevant, with the guidelines and
commendations of international technical bodies”. This requirement
 s the advantage of ensuring that the rules and measures adopted
  the parties both have to conform to applicable international agree-
ents and to take account of internationally agreed technical standards.

198. Finally, the scope of the obligation to prevent pollution must
  determined in light of the definition of pollution given in Article 40
 the 1975 Statute. Article 40 provides that : “For the purposes of this
atute, pollution shall mean the direct or indirect introduction by
an into the aquatic environment of substances or energy which have
rmful effects.” The term “harmful effects” is defined in the CARU
 gest as :
   “any alteration of the water quality that prevents or hinders any
   legitimate use of the water, that causes deleterious effects or harm to
   living resources, risks to human health, or a threat to water activities
   including fishing or reduction of recreational activities” (Title I,
   Chapter 1, Section 2, Article 1 (c) of the Digest (E3)).

 199. The Digest expresses the will of the Parties and their interpreta-
 n of the provisions of the 1975 Statute. Article 41, not unlike many
her provisions of the 1975 Statute, lays down broad obligations
 reed to by the Parties to regulate and limit their use of the river and
   protect its environment. These broad obligations are given more
ecific content through the co-ordinated rule-making action of
ARU as established under Article 56 of the 1975 Statute or through
e regulatory action of each of the parties, or by both means. The
 o regulatory actions are meant to complement each other. As
  cussed below (see paragraphs 201 to 202, and 214), CARU standards
 ncern mainly water quality. The CARU Digest sets only general
mits on certain discharges or effluents from industrial plants such as :
 ydrocarbons”, “sedimentable solids”, and “oils and greases”. As the
 gest makes explicit, those matters are left to each party to regulate.
  e Digest provides that, as regards effluents within its jurisdiction,
ch party shall take the appropriate “corrective measures” in order
   assure compliance with water quality standards (CARU Digest,
 c. E3: Pollution, Title 2, Chapter 5, Section 1, Article 3). Uruguay has
ken that action in its Regulation on Water Quality (Decree No. 253/79)
 d in relation to the Orion (Botnia) mill in the conditions stipulated in
e authorization issued by MVOTMA. In Argentina, the Entre Ríos
 ovince, which borders the river opposite the plant, has regulated indus-
 al discharges in a decree that also recognizes the binding effect of the

                                                                        70

ARU Digest (Regulatory Decree No. 5837, Government of Entre Ríos,
  December 1991, and Regulatory Decree No. 5394, Government
 Entre Ríos, 7 April 1997).

200. The Court considers it appropriate to now address the question
 the rules by which any allegations of breach are to be measured and,
ore specifically, by which the existence of “harmful effects” is to be
termined. It is the view of the Court that these rules are to be found in
e 1975 Statute, in the co-ordinated position of the Parties established
rough CARU (as the introductory phrases to Article 41 and Article 56
 the Statute contemplate) and in the regulations adopted by each Party
thin the limits prescribed by the 1975 Statute (as paragraphs (a), (b)
d (c) of Article 41 contemplate).

201. The functions of CARU under Article 56 (a) include making
 es governing the prevention of pollution and the conservation
d preservation of living resources. In the exercise of its rule-making
wer, the Commission adopted in 1984 the Digest on the uses of the
 ters of the River Uruguay and has amended it since. In 1990, when
ction E3 of the Digest was adopted, the Parties recognized that it
 s drawn up under Article 7 (f) of the 1961 Treaty and Articles 35,
, 41 to 45 and 56 (a) (4) of the 1975 Statute. As stated in the
gest, the “basic purposes” of Section E3 of the Digest are to be as
 lows :

  “(a) to protect and preserve the water and its ecological balance ;

    (b) to ensure any legitimate use of the water considering long term
        needs and particularly human consumption needs ;

    (c) to prevent all new forms of pollution and to achieve its reduc-
        tion in case the standard values adopted for the different legiti-
        mate uses of the River’s water are exceeded ;
    (d) to promote scientific research on pollution.” (Title I, Chap-
        ter 2, Section 1, Article 1.)
202. The standards laid down in the Digest are not, however, exhaus-
 e. As pointed out earlier, they are to be complemented by the rules and
easures to be adopted by each of the Parties within their domestic laws.

The Court will apply, in addition to the 1975 Statute, these two sets of
es to determine whether the obligations undertaken by the Parties
ve been breached in terms of the discharge of effluent by the mill as
ll as in respect of the impact of those discharges on the quality of the
ters of the river, on its ecological balance and on its biodiversity.

                                                                       71

(a) Environmental Impact Assessment

 203. The Court will now turn to the relationship between the need for
  environmental impact assessment, where the planned activity is liable
  cause harm to a shared resource and transboundary harm, and the
 ligations of the Parties under Article 41 (a) and (b) of the 1975 Stat-
e. The Parties agree on the necessity of conducting an environmental
 pact assessment. Argentina maintains that the obligations under the
 75 Statute viewed together impose an obligation to conduct an envi-
nmental impact assessment prior to authorizing Botnia to construct the
ant. Uruguay also accepts that it is under such an obligation. The
 rties disagree, however, with regard to the scope and content of the
vironmental impact assessment that Uruguay should have carried out
th respect to the Orion (Botnia) mill project. Argentina maintains in
e first place that Uruguay failed to ensure that “full environmental
sessments [had been] produced, prior to its decision to authorize the
nstruction . . .” ; and in the second place that “Uruguay’s decisions
ere] . . . based on unsatisfactory environmental assessments”, in par-
 ular because Uruguay failed to take account of all potential impacts
om the mill, even though international law and practice require it, and
 ers in this context to the 1991 Convention on Environmental Impact
 sessment in a Transboundary Context of the United Nations Eco-
 mic Commission for Europe (hereinafter the “Espoo Convention”)
 NTS, Vol. 1989, p. 309), and the 1987 Goals and Principles of Envi-
nmental Impact Assessment of the United Nations Environment Pro-
amme (hereinafter the “UNEP Goals and Principles”) (UNEP/
 G.152/4 Annex (1987), document adopted by UNEP Governing
ouncil at its 14th Session (Dec. 14/25 (1987)). Uruguay accepts that, in
cordance with international practice, an environmental impact assess-
ent of the Orion (Botnia) mill was necessary, but argues that interna-
 nal law does not impose any conditions upon the content of
ch an assessment, the preparation of which being a national, not
 ernational, procedure, at least where the project in question is not
 e common to several States. According to Uruguay, the only
quirements international law imposes on it are that there must
   assessments of the project’s potential harmful transboundary
 ects on people, property and the environment of other States, as
quired by State practice and the International Law Commission 2001
aft Articles on Prevention of Transboundary Harm from Hazardous
 tivities, without there being any need to assess remote or purely
eculative risks.

204. It is the opinion of the Court that in order for the Parties prop-
y to comply with their obligations under Article 41 (a) and (b) of the
75 Statute, they must, for the purposes of protecting and preserving the

                                                                     72

 uatic environment with respect to activities which may be liable to
use transboundary harm, carry out an environmental impact assess-
ent. As the Court has observed in the case concerning the Dispute
 garding Navigational and Related Rights,
   “there are situations in which the parties’ intent upon conclusion of
   the treaty was, or may be presumed to have been, to give the terms
   used — or some of them — a meaning or content capable of evolv-
   ing, not one fixed once and for all, so as to make allowance for,
   among other things, developments in international law” (Dispute
   Regarding Navigational and Related Rights (Costa Rica v. Nicara-
   gua), Judgment, I.C.J. Reports 2009, p. 242, para. 64).
 this sense, the obligation to protect and preserve, under Article 41 (a)
 the Statute, has to be interpreted in accordance with a practice, which
 recent years has gained so much acceptance among States that it may
 w be considered a requirement under general international law to
 dertake an environmental impact assessment where there is a risk that
e proposed industrial activity may have a significant adverse impact in
 ransboundary context, in particular, on a shared resource. Moreover,
 e diligence, and the duty of vigilance and prevention which it implies,
ould not be considered to have been exercised, if a party planning
orks liable to affect the régime of the river or the quality of its waters
d not undertake an environmental impact assessment on the potential
 ects of such works.

205. The Court observes that neither the 1975 Statute nor general
 ernational law specify the scope and content of an environmental
 pact assessment. It points out moreover that Argentina and Uruguay
e not parties to the Espoo Convention. Finally, the Court notes that
e other instrument to which Argentina refers in support of its argu-
ents, namely, the UNEP Goals and Principles, is not binding on the
 rties, but, as guidelines issued by an international technical body, has
 be taken into account by each Party in accordance with Article 41 (a)
 adopting measures within its domestic regulatory framework. More-
 er, this instrument provides only that the “environmental effects in an
 A should be assessed with a degree of detail commensurate with their
 ely environmental significance” (Principle 5) without giving any indica-
 n of minimum core components of the assessment. Consequently, it is
e view of the Court that it is for each State to determine in its domestic
 islation or in the authorization process for the project, the specific
ntent of the environmental impact assessment required in each case,
 ving regard to the nature and magnitude of the proposed development
 d its likely adverse impact on the environment as well as to the need
  exercise due diligence in conducting such an assessment. The Court
 o considers that an environmental impact assessment must be
nducted prior to the implementation of a project. Moreover, once

                                                                       73

erations have started and, where necessary, throughout the life of the
oject, continuous monitoring of its effects on the environment shall be
dertaken.

206. The Court has already considered the role of the environmental
 pact assessment in the context of the procedural obligations of the
 rties under the 1975 Statute (paragraphs 119 and 120). It will now deal
th the specific points in dispute with regard to the role of this type of
sessment in the fulfilment of the substantive obligations of the Parties,
at is to say, first, whether such an assessment should have, as a matter
 method, necessarily considered possible alternative sites, taking into
count the receiving capacity of the river in the area where the plant was
 be built and, secondly, whether the populations likely to be affected, in
 s case both the Uruguayan and Argentine riparian populations, should
ve, or have in fact, been consulted in the context of the environmental
 pact assessment.

  (i) The siting of the Orion (Botnia) mill at Fray Bentos

207. According to Argentina, one reason why Uruguay’s environmen-
 impact assessment is inadequate is that it contains no analysis of alter-
tives for the choice of the mill site, whereas the study of alternative
es is required under international law (UNEP Goals and Principles,
poo Convention, IFC Operational Policy 4.01). Argentina contends
at the chosen site is particularly sensitive from an ecological point of
 w and unconducive to the dispersion of pollutants “[b]ecause of the
ture of the waters which will receive the pollution, the propensity of
e site to sedimentation and eutrophication, the phenomenon of reverse
 w and the proximity of the largest settlement on the River Uruguay”.

208. Uruguay counters that the Fray Bentos site was initially chosen
cause of the particularly large volume of water in the river at that
cation, which would serve to promote effluent dilution. Uruguay
 ds that the site is moreover easily accessible for river navigation, which
cilitates delivery of raw materials, and local manpower is available
ere. Uruguay considers that, if there is an obligation to consider
 ernative sites, the instruments invoked for that purpose by Argentina
  not require alternative locations to be considered as part of an
vironmental impact assessment unless it is necessary in the circum-
 nces to do so. Finally, Uruguay affirms that in any case it did so
 d that the suitability of the Orion (Botnia) site was comprehensively
sessed.
209. The Court will now consider, first, whether Uruguay failed to
ercise due diligence in conducting the environmental impact assess-
ent, particularly with respect to the choice of the location of the plant

                                                                        74

 d, secondly, whether the particular location chosen for the siting of the
ant, in this case Fray Bentos, was unsuitable for the construction of a
ant discharging industrial effluent of this nature and on this scale, or
uld have a harmful impact on the river.
 210. Regarding the first point, the Court has already indicated that the
 poo Convention is not applicable to the present case (see paragraph 205
 ove) ; while with respect to the UNEP Goals and Principles to which
 gentina has referred, whose legal character has been described in para-
aph 205 above, the Court recalls that Principle 4 (c) simply provides
at an environmental impact assessment should include, at a minimum,
a] description of practical alternatives, as appropriate”. It is also to be
called that Uruguay has repeatedly indicated that the suitability of the
 ay Bentos location was comprehensively assessed and that other pos-
 le sites were considered. The Court further notes that the IFC’s Final
umulative Impact Study of September 2006 (hereinafter “CIS”) shows
at in 2003 Botnia evaluated four locations in total at La Paloma, at
 so de los Toros, at Nueva Palmira, and at Fray Bentos, before choos-
g Fray Bentos. The evaluations concluded that the limited amount of
 sh water in La Paloma and its importance as a habitat for birds ren-
red it unsuitable, while for Nueva Palmira its consideration was dis-
uraged by its proximity to residential, recreational, and culturally
 portant areas, and with respect to Paso de los Toros insufficient flow
  water during the dry season and potential conflict with competing
 ter uses, as well as a lack of infrastructure, led to its exclusion. Con-
quently, the Court is not convinced by Argentina’s argument that an
sessment of possible sites was not carried out prior to the determina-
 n of the final site.

211. Regarding the second point, the Court cannot fail to note that
 y decision on the actual location of such a plant along the River Uru-
 ay should take into account the capacity of the waters of the river to
ceive, dilute and disperse discharges of effluent from a plant of this
 ture and scale.
212. The Court notes, with regard to the receiving capacity of the
 er at the location of the mill, that the Parties disagree on the geo-
orphological and hydrodynamic characteristics of the river in the
 evant area, particularly as they relate to river flow, and how the
 w of the river, including its direction and its velocity, in turn
termines the dispersal and dilution of pollutants. The differing views
 t forward by the Parties with regard to the river flow may be due to
e different modelling systems which each has employed to analyse
e hydrodynamic features of the River Uruguay at the Fray Bentos
cation. Argentina implemented a three-dimensional modelling that
easured speed and direction at ten different depths of the river
 d used a sonar — an Acoustic Doppler Current Profiler (hereafter

                                                                        75

ADCP”) — to record water flow velocities for a range of depths for
 out a year. The three-dimensional system generated a large number of
 ta later introduced in a numerical hydrodynamic model. On the
her hand, Botnia based its environmental impact assessment on a bi-
mensional modelling — the RMA2. The EcoMetrix CIS implemented
 th three-dimensional and bi-dimensional models. However, it
  not mentioned whether an ADCP sonar was used at different
 pths.

 213. The Court sees no need to go into a detailed examination of the
 entific and technical validity of the different kinds of modelling, cali-
ation and validation undertaken by the Parties to characterize the rate
 d direction of flow of the waters of the river in the relevant area. The
ourt notes however that both Parties agree that reverse flows occur fre-
 ently and that phenomena of low flow and stagnation may be observed
 the concerned area, but that they disagree on the implications of this
r the discharges from the Orion (Botnia) mill into this area of the river.

 214. The Court considers that in establishing its water quality stand-
ds in accordance with Articles 36 and 56 of the 1975 Statute, CARU
ust have taken into account the receiving capacity and sensitivity of the
 ters of the river, including in the areas of the river adjacent to Fray
 ntos. Consequently, in so far as it is not established that the discharges
 effluent of the Orion (Botnia) mill have exceeded the limits set by those
 ndards, in terms of the level of concentrations, the Court finds itself
 able to conclude that Uruguay has violated its obligations under the
 75 Statute. Moreover, neither of the Parties has argued before the
ourt that the water quality standards established by CARU have not
 equately taken into consideration the geomorphological and hydro-
gical characteristics of the river and the capacity of its waters to dis-
rse and dilute different types of discharges. The Court is of the opinion
at, should such inadequacy be detected, particularly with respect to cer-
 n areas of the river such as at Fray Bentos, the Parties should initiate
review of the water quality standards set by CARU and ensure that
ch standards clearly reflect the characteristics of the river and are capa-
e of protecting its waters and its ecosystem.

   (ii) Consultation of the affected populations

 215. The Parties disagree on the extent to which the populations
 ely to be affected by the construction of the Orion (Botnia) mill,
 rticularly on the Argentine side of the river, were consulted in the
 urse of the environmental impact assessment. While both Parties
 ree that consultation of the affected populations should form part
  an environmental impact assessment, Argentina asserts that inter-
 tional law imposes specific obligations on States in this regard.
  support of this argument, Argentina points to Articles 2.6 and 3.8 of

                                                                        76

e Espoo Convention, Article 13 of the 2001 International Law
ommission draft Articles on Prevention of Transboundary Harm
om Hazardous Activities, and Principles 7 and 8 of the UNEP Goals
 d Principles. Uruguay considers that the provisions invoked by
 gentina cannot serve as a legal basis for an obligation to consult the
 ected populations and adds that in any event the affected populations
 d indeed been consulted.

216. The Court is of the view that no legal obligation to consult the
 ected populations arises for the Parties from the instruments invoked
  Argentina.
217. Regarding the facts, the Court notes that both before and after
e granting of the initial environmental authorization, Uruguay did under-
ke activities aimed at consulting the affected populations, both on the
 gentine and the Uruguayan sides of the river. These activities included
eetings on 2 December 2003 in Río Negro, and on 26 May 2004 in Fray
 ntos, with participation of Argentine non-governmental organizations.
  addition, on 21 December 2004, a public hearing was convened in
 ay Bentos which, according to Uruguay, addressed among other sub-
 ts, the
  “handling of chemical products in the plant and in the port ; the
  appearance of acid rain, dioxins, furans and other polychlorates of
  high toxicity that could affect the environment ; compliance with the
  Stockholm Convention ; atmospheric emissions of the plant ; electro-
  magnetic and electrostatic emissions ; [and] liquid discharges into the
  river”.

habitants of Fray Bentos and nearby regions of Uruguay and Argen-
 a participated in the meeting and submitted 138 documents containing
 estions or concerns.
218. Further, the Court notes that between June and November 2005
ore than 80 interviews were conducted by the Consensus Building
stitute, a non-profit organization specializing in facilitated dialogues,
ediation, and negotiation, contracted by the IFC. Such interviews
 re conducted inter alia in Fray Bentos, Gualeguaychú, Montevideo,
 d Buenos Aires, with interviewees including civil society groups,
 n-governmental organizations, business associations, public officials,
urism operators, local business owners, fishermen, farmers and
antation owners on both sides of the river. In December 2005, the
aft CIS and the report prepared by the Consensus Building
stitute were released, and the IFC opened a period of consultation
  receive additional feedback from stakeholders in Argentina and
 uguay.

219. In the light of the above, the Court finds that consultation by
uguay of the affected populations did indeed take place.

                                                                      77

 (b) Question of the production technology used in the Orion (Botnia)
     mill

 220. Argentina maintains that Uruguay has failed to take all measures
  prevent pollution by not requiring the mill to employ the “best avail-
 le techniques”, even though this is required under Article 5 (d) of the
OPs Convention, the provisions of which are incorporated by virtue of
e “referral clause” in Article 41 (a) of the 1975 Statute. According to
 gentina, the experts’ reports it cites establish that the mill does not use
 st available techniques and that its performance is not up to interna-
 nal standards, in the light of the various techniques available for pro-
 cing pulp. Uruguay contests these claims. Relying on the CIS, the
cond Hatfield report and the audit conducted by AMEC at the IFC’s
quest, Uruguay asserts that the Orion (Botnia) mill is, by virtue of the
  hnology employed there, one of the best pulp mills in the world,
 plying best available techniques and complying with European Union
  ndards, among others, in the area.

 221. Argentina, however, specifically criticizes the absence of any “ter-
 ry treatment of effluent” (i.e., a third round of processing production
  ste before discharge into the natural environment), which is necessary
  reduce the quantity of nutrients, including phosphorus, since the efflu-
 t is discharged into a highly sensitive environment. The mill also lacks,
 cording to Argentina, an empty emergency basin, designed to contain
fluent spills. Answering a question asked by a judge, Argentina consid-
   that a tertiary treatment would be possible, but that Uruguay failed to
 nduct an adequate assessment of tertiary treatment options for the
 ion (Botnia) mill.

222. Uruguay observes that “the experts did not consider it necessary
  equip the mill with a tertiary treatment phase”. Answering the same
 estion, Uruguay argued that, though feasible, the addition of a tertiary
 atment facility would not be environmentally advantageous overall, as
would significantly increase the energy consumption of the plant, its
rbon emissions, together with sludge generation and chemical use.
 uguay has consistently maintained that the bleaching technology used
acceptable, that the emergency basins in place are adequate, that the
 ll’s production of synthetic chemical compounds meets technological
quirements and that the potential risk from this production was indeed
sessed.

223. To begin with, the Court observes that the obligation to prevent
llution and protect and preserve the aquatic environment of the River
uguay, laid down in Article 41 (a), and the exercise of due diligence
plied in it, entail a careful consideration of the technology to be used

                                                                         78

  the industrial plant to be established, particularly in a sector such as
 lp manufacturing, which often involves the use or production of sub-
  nces which have an impact on the environment. This is all the more
 portant in view of the fact that Article 41 (a) provides that the regu-
 ory framework to be adopted by the Parties has to be in keeping with
 e guidelines and recommendations of international technical bodies.

224. The Court notes that the Orion (Botnia) mill uses the bleached
 aft pulping process. According to the December 2001 Integrated Pol-
 ion Prevention and Control Reference Document on Best Available
 chniques in the Pulp and Paper Industry of the European Commission
ereinafter “IPPC-BAT”), which the Parties referred to as the industry
 ndard in this sector, the Kraft process already accounted at that time
r about 80 per cent of the world’s pulp production and is therefore the
ost applied production method of chemical pulping processes. The
ant employs an ECF-light (Elemental chlorine-free) bleaching process
d a primary and secondary wastewater treatment involving activated
 dge treatment.

 225. The Court finds that, from the point of view of the technology
mployed, and based on the documents submitted to it by the Parties,
 rticularly the IPPC-BAT, there is no evidence to support the claim of
  gentina that the Orion (Botnia) mill is not BAT-compliant in terms of
 e discharges of effluent for each tonne of pulp produced. This finding is
 pported by the fact that, as shown below, no clear evidence has been
 esented by Argentina establishing that the Orion (Botnia) mill is not in
 mpliance with the 1975 Statute, the CARU Digest and applicable regu-
 ions of the Parties in terms of the concentration of effluents per litre of
  stewater discharged from the plant and the absolute amount of efflu-
 ts that can be discharged in a day.

226. The Court recalls that Uruguay has submitted extensive data
garding the monitoring of effluent from the Orion (Botnia) mill, as
ntained in the various reports by EcoMetrix and DINAMA
coMetrix, Independent Performance Monitoring as required by the
 C Phase 2 : Six Month Environmental Performance Review (July
08) ; EcoMetrix, Independent Performance Monitoring as required
   the IFC, Phase 3 : Environmental Performance Review (2008
onitoring Year) (hereinafter “EcoMetrix Third Monitoring Report”) ;
 NAMA, Performance Report for the First Year of Operation
  the Botnia Plant and the Environmental Quality of the Area of
fluence, May 2009 ; DINAMA, Six Month Report on the Botnia
mission Control and Environmental Performance Plan), and that
 gentina expressed the view, in this regard, that Uruguay had on this
atter, much greater, if not exclusive, access to the factual evidence. How-
er, the Court notes that Argentina has itself generated much factual
 ormation and that the materials which Uruguay produced have

                                                                         79

en available to Argentina at various stages of the proceedings or
ve been available in the public domain. Therefore the Court does
t consider that Argentina has been at a disadvantage with regard to the
oduction of evidence relating to the discharges of effluent of the mill.

227. To determine whether the concentrations of pollutants discharged
 the Orion (Botnia) mill are within the regulatory limits, the Court will
ve to assess them against the effluent discharge limits — both in terms
 the concentration of effluents in each litre of wastewater discharged
d the absolute amount of effluents that can be discharged in a day —
escribed by the applicable regulatory standards of the Parties, as char-
terized by the Court in paragraph 200 above, and the permits issued
r the plant by the Uruguayan authorities, since the Digest only sets
neral limits on “hydrocarbons”, “sedimentable solids”, and “oils and
eases”, but does not establish specific ones for the substances in conten-
 n between the Parties. Argentina did not allege any non-compliance of
e Orion (Botnia) mill with CARU’s effluent standards (CARU Digest,
c. E3 (1984, as amended)).

 228. Taking into account the data collected after the start-up of the
 ll as contained in the various reports by DINAMA and EcoMetrix, it
 es not appear that the discharges from the Orion (Botnia) mill have
ceeded the limits set by the effluent standards prescribed by the rele-
 nt Uruguayan regulation as characterized by the Court in para-
aph 200 above, or the initial environmental authorization issued by
VOTMA (MVOTMA, Initial Environmental Authorization for the
 tnia Plant (14 February 2005)), except for a few instances in which the
ncentrations have exceeded the limits. The only parameters for which a
corded measurement exceeded the standards set by Decree No. 253/79
  the initial environmental authorization by MVOTMA are : nitrogen,
 rates, and AOX (Adsorbable Organic Halogens). In those cases, meas-
ements taken on one day exceeded the threshold. However, the initial
vironmental authorization of 14 February 2005 specifically allows
arly averaging for the parameters. The most notable of these cases in
hich the limits were exceeded is the one relating to AOX, which is the
 rameter used internationally to monitor pulp mill effluent, sometimes
cluding persistent organic pollutants (POPs). According to the IPPC-
AT reference document submitted by the Parties, and considered
   them as the industry standard in this sector, “the environmental
ntrol authorities in many countries have set severe restrictions on
e discharges of chlorinated organics measured as AOX into the
 uatic environment”. Concentrations of AOX reached at one
 int on 9 January 2008, after the mill began operations, as high
level as 13 mg/L, whereas the maximum limit used in the environ-

                                                                       80

ental impact assessment and subsequently prescribed by MVOTMA was
mg/L. However, in the absence of convincing evidence that this is not
 isolated episode but rather a more enduring problem, the Court is not
 a position to conclude that Uruguay has breached the provisions
 the 1975 Statute.

(c) Impact of the discharges on the quality of the waters of the river
229. As pointed out earlier (see paragraph 165), the Parties have over
e last three years presented to the Court a vast amount of factual and
 entific material containing data and analysis of the baseline levels of
ntaminants already present in the river prior to the commissioning of
e plant and the results of measurements of its water and air emissions
 er the plant started its production activities and, in some cases, until
 d-2009.
230. Regarding the baseline data, the studies and reports submitted by
e Parties contained data and analysis relating, inter alia, to water qual-
 , air quality, phytoplankton and zooplankton of the river, health indi-
tors and biomarkers of pollution in fish from the river, monitoring of
h fauna in the area around the Orion (Botnia) mill, fish community and
ecies diversity in the river, concentrations of resin acids, chlorinated
 enols and plant sterols in fish from the river, survey of species belong-
g to the genus Tillandsia, the Orion (Botnia) mill pre-start-up audit,
d analysis of mercury and lead in fish muscle.

231. Argentina contends that Uruguay’s baseline data were both inade-
 ate and incomplete in many aspects. Uruguay rejects this allegation,
d argues that Argentina has actually relied on Uruguay’s baseline data
  give its own assessment of water quality. According to Uruguay,
ntrary to Argentina’s assertions, collection of baseline data by
 uguay started in August 2006, when DINAMA started to conduct
r a period of 15 months pre-operational water quality monitoring
 or to the commissioning of the plant in November 2007, which
 ved to complement almost 15 years of more general monitoring
at had been carried out within CARU under the PROCON
ogramme (River Uruguay Water Quality and Pollution Control
ogramme, from the Spanish acronym for “Programa de Calidad
 Aguas y Control de la Contaminación del Río Uruguay”). Argentina
d not challenge counsel for Uruguay’s statement during the oral
oceedings that it used Uruguay’s baseline data for the assessment of
 ter quality.

232. The data presented by the Parties on the post-operation monitor-

                                                                       81

g of the actual performance of the plant in terms of the impact of its
missions on the river includes data obtained through different testing
 ogrammes conducted, inter alia, by an Argentine scientific team from
 o national universities, contracted by the National Secretariat of Envi-
 nment and Sustainable Development of Argentina (ten sites), the OSE
  ruguay’s State Agency for Sanitary Works, from the Spanish acronym
 r “Obras Sanitarias del Estado”), DINAMA, independently of Botnia
6 sites), and Botnia, reporting to DINAMA and the IFC (four sites ;
 d testing the effluent).

 233. The monitoring sites maintained by Argentina are located on the
 gentine side of the river ; with the most upstream position located
  km from the plant and the furthest downstream one at about 16 km
om the plant. Nevertheless, three of the sites (U0, U2 and U3) are near
e plant ; while another three are in Nandubaysal Bay and Inés Lagoon,
e data from which, according to Argentina’s counsel, “enabled the sci-
tists to clearly set the bay apart, as it acts as an ecosystem that is rela-
 ely detached from the Uruguay river” (Scientific and Technical Report,
hapter 3, appendix : “Background Biogeochemical Studies”, para. 4.1.2 ;
e also ibid., para. 4.3.1.2).

234. The monitoring sites maintained by Uruguay (DINAMA) and by
 tnia are located on the Uruguayan side. The OSE monitoring point is
cated at the drinking water supply intake pipe for Fray Bentos, at or
ar DINAMA station 11.
235. Argentina’s team gathered data from November 2007 until
pril 2009 with many of the results being obtained from October 2008.
 uguay, through DINAMA, has been carrying out its monitoring of the
e since March 2006. Its most recent data cover the period up
  June 2009. The OSE, in terms of its overall responsibility for Uru-
 ayan water quality, has been gathering relevant data which has been
ed in the periodic reports on the operation of the plant.

 236. The Court also has before it interpretations of the data provided
  experts appointed by the Parties, and provided by the Parties them-
 ves and their counsel. However, in assessing the probative value of the
  dence placed before it, the Court will principally weigh and evaluate
e data, rather than the conflicting interpretations given to it by the
 rties or their experts and consultants, in order to determine whether
  uguay breached its obligations under Articles 36 and 41 of the
 75 Statute in authorizing the construction and operation of the Orion
 otnia) mill.
 237. The particular parameters and substances that are subject to con-
oversy between the Parties in terms of the impact of the discharges of
fluent from the Orion (Botnia) mill on the quality of the waters of the

                                                                         82

 er are : dissolved oxygen ; total phosphorus (and the related matter of
trophication due to phosphate) ; phenolic substances ; nonylphenols
d nonylphenolethoxylates ; and dioxins and furans. The Court now
rns to the assessment of the evidence presented to it by the Parties with
 pect to these parameters and substances.

   (i) Dissolved oxygen

 238. Argentina raised for the first time during the oral proceedings the
 eged negative impact of the Orion (Botnia) mill on dissolved oxygen in
e river referring to data contained in the report of the Uruguayan OSE.
 cording to Argentina, since dissolved oxygen is environmentally ben-
cial and there is a CARU standard which sets a minimum level of dis-
 ved oxygen for the river waters (5.6 mg/L), the introduction by the
 ion (Botnia) mill into the aquatic environment of substances or energy
hich caused the dissolved oxygen level to fall below that minimum con-
tutes a breach of the obligation to prevent pollution and to preserve
e aquatic environment. Uruguay argues that Argentina’s figures taken
om the measurements of the OSE were for “oxidabilidad”, which refers
 the “demand for oxygen” and not for “oxígeno disuelto” — i.e., dis-
 ved oxygen. Uruguay also claims that a drop in the level of demand
r oxygen shows an improvement in the quality of the water, since the
 el of demand should be kept as low as possible.

239. The Court observes that a post-operational average value of
8 mg/L for dissolved oxygen would indeed, if proven, constitute a viola-
 n of CARU standards, since it is below the minimum value of 5.6 mg
 dissolved oxygen per litre required according to the CARU Digest (E3,
tle 2, Chapter 4, Section 2). However, the Court finds that the allega-
 n made by Argentina remains unproven. First, the figures on which
 gentina bases itself do not correspond to the ones for dissolved oxygen
at appear in the EcoMetrix Third Monitoring Report, where the sam-
es taken between February and October 2008 were all above the
ARU minimum standard for dissolved oxygen. Secondly, DINAMA’s
 rface Water and Sediment Quality Data Report of July 2009 (Six
onth Report : January-June) (hereinafter “DINAMA’s Water Quality
 port”) (see p. 7, fig. 4.5 : average of 9.4 mg/L) displays concentrations
  dissolved oxygen that are well above the minimum level required
 der the CARU Digest. Thirdly, Argentina’s 30 June 2009 report
ys in its summary that the records of water quality parameters over
e period were “normal for the river with typical seasonal patterns
  temperature and associated dissolved oxygen”. The hundreds of
easurements presented in the figures in that chapter of the “Colombo
 port” support that conclusion even taking account of some slightly
wer figures. Fourthly, the figures relating to dissolved oxygen
ntained in DINAMA’s Water Quality Report have essentially
e same characteristics as those gathered by Argentina — they

                                                                       83

e above the CARU minimum and are the same upstream and down-
 eam. Thus, the Court concludes that there appears to be no significant
 ference between the sets of data over time and that there is no evidence
  support the contention that the reference to “oxidabilidad” in the
SE report referred to by Argentina should be interpreted to mean “dis-
 ved oxygen”.

   (ii) Phosphorus

 240. There is agreement between the Parties that total phosphorus lev-
    in the River Uruguay are high. According to Uruguay, the total
mount of (natural and anthropogenic) phosphorus emitted into the river
 r year is approximately 19,000 tonnes, of which the Orion (Botnia) mill
 s a share of some 15 tonnes (in 2008) or even less, as was expected for
 09. These figures have not been disputed by Argentina during the pro-
edings. Uruguay contends further that no violation of the provisions
  the 1975 Statute can be alleged since the high concentration cannot
   clearly attributed to the Orion (Botnia) mill as the source, and since
   standard is set by CARU for phosphorus. Uruguay maintains also
at based on data provided by DINAMA as compared to baseline
 ta also compiled by DINAMA, it can be demonstrated that “[t]otal
 osphorus levels were generally lower post-start-up as compared
    the 2005-2006 baseline” (EcoMetrix Third Monitoring Report,
 arch 2009).
 241. A major disagreement between the Parties relates to the relation-
  p between the higher concentration of phosphorus in the waters of the
 er and the algal bloom of February 2009 and whether operation of the
 ion (Botnia) mill has caused the eutrophication of the river. Argentina
  ims that the Orion (Botnia) mill is the cause of the eutrophication and
gher concentration of phosphates, while Uruguay denies the attribut-
 ility of these concentrations as well as the eutrophication to the opera-
 n of the plant in Fray Bentos.
 242. The Court notes that CARU has not adopted a water quality
  ndard relating to levels of total phosphorus and phosphates in the
 er. Similarly, Argentina has no water quality standards for total phos-
 orus. The Court will therefore have to use the water quality and efflu-
 t limits for total phosphorus enacted by Uruguay under its domestic
  islation, as characterized by the Court in paragraph 200 above, to
sess whether the concentration levels of total phosphorus have exceeded
e limits laid down in the regulations of the Parties adopted in accord-
 ce with Article 41 (a) of the 1975 Statute. The water quality standard
r total phosphorus under the Uruguayan Regulation is 0.025 mg/L for
rtain purposes such as drinking water, irrigation of crops for human
 nsumption and water used for recreational purposes which involve
  ect human contact with the water (Decree No. 253/79, Regulation of

                                                                       84

ater Quality). The Uruguayan Decree also establishes a total phospho-
s discharge standard of 5 mg/L (Decree No. 253/79 Regulation of
ater Quality, Art. 11 (2)). The Orion (Botnia) mill must comply with
th standards.

243. The Court finds that based on the evidence before it, the Orion
otnia) mill has so far complied with the standard for total phosphorus
 effluent discharge. In this context, the Court notes that, for 2008
cording to the EcoMetrix Third Monitoring Report, the Uruguayan
ta recorded an average of 0.59 mg/L total phosphorus in effluent dis-
arge from the plant. Moreover, according to the DINAMA 2009 Emis-
 ns Report, the effluent figures for November 2008 to May 2009 were
tween 0.053 mg/L and 0.41 mg/L (e.g., DINAMA, “Six Month Report
  the Botnia Emission Control and Environmental Performance Plan
ovember 11, 2008 to May 31, 2009” (22 July 2009) p. 5 ; see also pp. 25
d 26). Argentina does not contest these figures which clearly show val-
s much below the standard established under the Uruguayan Decree.

244. The Court observes in this connection that as early as 11 Febru-
y 2005, DINAMA, in its environmental impact assessment for the
 ion (Botnia) mill, noted the heavy load of nutrients (phosphorus and
 rogen) in the river and stated that :
     “This situation has generated the frequent proliferation of algae,
  in some cases with an important degree of toxicity as a result of the
  proliferation of cyanobacteria. These proliferations, which in recent
  years have shown an increase in both frequency and intensity, con-
  stitute a health risk and result in important economic losses since
  they interfere with some uses of water, such as recreational activities
  and the public supply of drinking water. To this already existing
  situation it must be added that, in the future, the effluent in the plant
  will emit a total of 200 t/a of N[itrogen] and 20 t/a of P[hosphorus],
  values that are the approximate equivalent of the emission of the un-
  treated sewage of a city of 65,000 people.” (P. 20, para. 6.1.)

245. The DINAMA Report then continues as follows :
     “It is also understood that it is not appropriate to authorize any
  waste disposal that would increase any of the parameters that present
  critical values, even in cases in which the increase is considered insig-
  nificant by the company. Nevertheless, considering that the para-
  meters in which the quality of water is compromised are not specific
  to the effluents of this project, but rather would be affected by the
  waste disposal of any industrial or domestic effluent under consid-
  eration, it is understood that the waste disposal proposed in the
  project may be accepted, as long as there is compensation for any

                                                                        85

   increase over and above the standard value for any of the critical
   parameters.” (DINAMA Report, p. 21.)

 246. The Court further notes that the initial environmental authoriza-
 n, granted on 15 February 2005, required compliance by Botnia with
ose conditions, with CARU standards and with best available tech-
ques as included in the December 2001 IPPC-BAT of the European
ommission. It also required the completion of an implementation plan
r mitigation and compensation measures. That plan was completed by
e end of 2007 and the authorization to operate was granted on 8 Novem-
r 2007. On 29 April 2008, Botnia and the OSE concluded an Agree-
ent Regarding Treatment of the Municipal Wastewater of Fray Bentos,
med at reducing total phosphorus and other contaminants.

247. The Court considers that the amount of total phosphorus dis-
arge into the river that may be attributed to the Orion (Botnia) mill is
 ignificant in proportionate terms as compared to the overall total
 osphorus in the river from other sources. Consequently, the Court
ncludes that the fact that the level of concentration of total phosphorus
  the river exceeds the limits established in Uruguayan legislation in
 pect of water quality standards cannot be considered as a violation of
 ticle 41 (a) of the 1975 Statute in view of the river’s relatively high
 al phosphorus content prior to the commissioning of the plant, and
king into account the action being taken by Uruguay by way of com-
nsation.
248. The Court will now turn to the consideration of the issue of the
gal bloom of 4 February 2009. Argentina claims that the algal bloom of
February 2009 was caused by the Orion (Botnia) mill’s emissions of
 trients into the river. To substantiate this claim Argentina points to the
esence of effluent products in the blue-green algal bloom and to vari-
 s satellite images showing the concentration of chlorophyll in the
 ter. Such blooms, according to Argentina, are produced during the
 rm season by the explosive growth of algae, particularly cyanobact-
 a, responding to nutrient enrichment, mainly phosphate, among other
mpounds present in detergents and fertilizers.
249. Uruguay contends that the algal bloom of February 2009, and
e high concentration of chlorophyll, was not caused by the Orion (Bot-
a) mill but could have originated far upstream and may have most
 ely been caused by the increase of people present in Gualeyguaychú
 ring the yearly carnival held in that town, and the resulting increase in
wage, and not by the mill’s effluents. Uruguay maintains that Argen-
 e data actually prove that the Orion (Botnia) mill has not added to the
ncentration of phosphorus in the river at any time since it began
 erating.

250. The Parties are in agreement on several points regarding the algal
oom of 4 February 2009, including the fact that the concentrations of

                                                                        86

 trients in the River Uruguay have been at high levels both before and
 er the bloom episode, and the fact that the bloom disappeared shortly
 er it had begun. The Parties also appear to agree on the interdepend-
ce between algae growth, higher temperatures, low and reverse flows,
d presence of high levels of nutrients such as nitrogen and phosphorus
 the river. It has not, however, been established to the satisfaction of
e Court that the algal bloom episode of 4 February 2009 was caused by
e nutrient discharges from the Orion (Botnia) mill.

   (iii) Phenolic substances

251. With regard to phenolic substances, Argentina contends that the
 ion (Botnia) mill’s emission of pollutants have resulted in violations of
e CARU standard for phenolic substances once the plant started oper-
 ng, while, according to Argentina, pre-operational baseline data did
 t show that standard to have been exceeded. Uruguay on the other
nd argues that there have been numerous violations of the standard,
roughout the river, long before the plant went into operation. Uruguay
bstantiates its arguments by pointing to several studies including the
 oMetrix final Cumulative Impact Study, which had concluded that
 enolic substances were found to have frequently exceeded the water
 ality standard of 0.001 mg/L fixed by CARU.
252. The Court also notes that Uruguayan data indicate that the water
 ality standard was being exceeded from long before the plant began
 erating. The Cumulative Impact Study prepared in September 2006 by
 oMetrix for the IFC states that phenolics were found frequently to
ceed the standard, with the highest values on the Argentine side of the
 er. The standard is still exceeded in some of the measurements in the
ost recent report before the Court but most are below it (DINAMA
ly 2009 Water Quality Report, p. 21, para. 4.1.11.2 and App. 1, show-
g measurements from 0.0005 to 0.012 mg/L).

253. During the oral proceedings, counsel for Argentina claimed that
e standard had not previously been exceeded and that the plant has
used the limit to be exceeded. The concentrations, he said, had increased
  average by three times and the highest figure was 20 times higher.
 uguay contends that the data contained in the DINAMA 2009 Report
ows that the post-operational levels of phenolic substances were lower
an the baseline levels throughout the river including at the OSE water
 ake.

 254. Based on the record, and the data presented by the Parties, the
ourt concludes that there is insufficient evidence to attribute the alleged

                                                                        87

crease in the level of concentrations of phenolic substances in the river
 the operations of the Orion (Botnia) mill.

   (iv) Presence of nonylphenols in the river environment

 255. Argentina claims that the Orion (Botnia) mill emits, or has emit-
d, nonylphenols and thus has caused damage to, or at least has sub-
 ntially put at risk, the river environment. According to Argentina, the
ost likely source of these emissions are surfactants (detergents), nonyl-
 enolethoxylates used to clean the wood pulp as well as the installations
  the plant itself. Argentina also contends that from 46 measurements
rformed in water samples the highest concentrations, in particular
ose exceeding the European Union relevant standards, were deter-
 ned in front-downstream the mill and in the bloom sample collected on
February 2009, with lower levels upstream and downstream, indicating
at the Orion (Botnia) mill effluent is the most probable source of these
 idues. In addition, according to Argentina, bottom sediments collected
 front-downstream the mill showed a rapid increase of nonylphenols
om September 2006 to February 2009, corroborating the increasing
 nd of these compounds in the River Uruguay. For Argentina, the spatial
 tribution of sub-lethal effects detected in rotifers (absence of
 nes), transplanted Asiatic clams (reduction of lipid reserves) and fish
 trogenic effects) coincided with the distribution area of nonylphenols
ggesting that these compounds may be a significant stress factor.

256. Uruguay rejects Argentina’s claim relating to nonylphenols and
 nylphenolethoxylates, and categorically denies the use of nonylphenols
d nonylphenolethoxylates by the Orion (Botnia) mill. In particular, it
ovides affidavits from Botnia officials to the effect that the mill does
 t use and has never used nonylphenols or nonylphenolethoxylate
rivatives in any of its processes for the production of pulp, including in
e pulp washing and cleaning stages, and that no cleaning agents con-
ning nonylphenols are or have been used for cleaning the plant’s
uipment (Affidavit of Mr. González, 2 October 2009).

257. The Court recalls that the issue of nonylphenols was included in
e record of the case before the Court only by the Report submitted by
 gentina on 30 June 2009. Although testing for nonylphenols had been
rried out since November 2008, Argentina has not however, in the
 w of the Court, adduced clear evidence which establishes a link
tween the nonylphenols found in the waters of the river and the Orion
otnia) mill. Uruguay has also categorically denied before the Court
e use of nonylphenolethoxylates for production or cleaning by the
 ion (Botnia) mill. The Court therefore concludes that the evidence in

                                                                       88

e record does not substantiate the claims made by Argentina on this
atter.
   (v) Dioxins and furans
 258. Argentina has alleged that while the concentration of dioxins and
rans in surface sediments is generally very low, data from its studies
monstrated an increasing trend compared to data compiled before the
 ion (Botnia) mill commenced operations. Argentina does not claim a
olation of standards, but relies on a sample of sábalo fish tested by its
onitoring team, which showed that one fish presented elevated levels of
oxins and furans which, according to Argentina, pointed to a rise in the
cidence of dioxins and furans in the river after the commissioning
  the Orion (Botnia) mill. Uruguay contests this claim, arguing that
ch elevated levels cannot be linked to the operation of the Orion
 otnia) mill, given the presence of so many other industries operating
ong the River Uruguay and in neighbouring Nandubaysal Bay, and
e highly migratory nature of the sábalo species which was tested.
  addition, Uruguay advances that its testing of the effluent coming
om the Orion (Botnia) mill demonstrate that no dioxins and furans
uld have been introduced into the mill effluent, as the levels detected
  the effluent were not measurably higher than the baseline levels in
e River Uruguay.

259. The Court considers that there is no clear evidence to link the
crease in the presence of dioxins and furans in the river to the operation
 the Orion (Botnia) mill.

(d) Effects on biodiversity
260. Argentina asserts that Uruguay “has failed to take all measures
 protect and preserve the biological diversity of the River Uruguay and
e areas affected by it”. According to Argentina, the treaty obligation
o protect and preserve the aquatic environment” comprises an obliga-
 n to protect the biological diversity including “habitats as well as species
  flora and fauna”. By virtue of the “referral clause” in Article
  (a), Argentina argues that the 1975 Statute requires Uruguay, in
 pect of activities undertaken in the river and areas affected by it, to
mply with the obligations deriving from the CITES Convention, the
odiversity Convention and the Ramsar Convention. Argentina main-
ns that through its monitoring programme abnormal effects were
tected in aquatic organisms — such as malformation of rotifers and
 s of fat by clams — and the biomagnification of persistent pollutants
ch as dioxins and furans was detected in detritus feeding fish (such as
e sábalo fish). Argentina also contends that the operation of the mill
 ses a threat, under conditions of reverse flow, to the Esteros de Farra-
 s site, situated “in the lower section of the River . . . downstream from

                                                                          89

e Salto Grande dam and on the frontier with Argentina”, a few kilo-
etres upstream from the Orion (Botnia) mill.

 261. Uruguay states that Argentina has failed to demonstrate any
each by Uruguay of the Biodiversity Convention, while the Ramsar
onvention has no bearing in the present case because Esteros de Farra-
 s was not included in the list of Ramsar sites whose ecological charac-
  is threatened. With regard to the possibility of the effluent plume from
e mill reaching Esteros de Farrapos, Uruguay in the oral proceedings
knowledged that under certain conditions that might occur. However,
 uguay added that it would be expected that the dilution of the effluent
om the mill of 1 :1000 would render the effluent quite harmless
 d below any concentration capable of constituting pollution. Uruguay
ntends that Argentina’s claims regarding the harmful effects on fish
 d rotifers as a result of the effluents from the Orion (Botnia) mill
e not credible. It points out that a recent comprehensive report of
 NAMA on ichthyofauna concludes that compared to 2008 and
 09 there has been no change in species biodiversity. Uruguay adds
at the July 2009 report of DINAMA, with results of its February 2009
onitoring of the sediments in the river where some fish species feed,
 ted that “the quality of the sediments at the bottom of the Uruguay
 ver has not been altered as a consequence of the industrial activity
 the Botnia plant”.

 262. The Court is of the opinion that as part of their obligation to pre-
 ve the aquatic environment, the Parties have a duty to protect the
una and flora of the river. The rules and measures which they have to
 opt under Article 41 should also reflect their international under-
kings in respect of biodiversity and habitat protection, in addition to
e other standards on water quality and discharges of effluent. The
ourt has not, however, found sufficient evidence to conclude that Uru-
 ay breached its obligation to preserve the aquatic environment includ-
g the protection of its fauna and flora. The record rather shows that a
 ar relationship has not been established between the discharges from
e Orion (Botnia) mill and the malformations of rotifers, or the dioxin
und in the sábalo fish or the loss of fat by clams reported in the findings
  the Argentine River Uruguay Environmental Surveillance (URES)
ogramme.

(e) Air pollution
263. Argentina claims that the Orion (Botnia) mill has caused air,
ise and visual pollution which negatively impact on “the aquatic envi-
nment” in violation of Article 41 of the 1975 Statute. Argentina also

                                                                        90

gues that the 1975 Statute was concluded not only to protect the qual-
  of the waters, but also, more generally, the “régime” of the river and
he areas affected by it, i.e., all the factors that affect, and are affected
  the ecosystem of the river as a whole”. Uruguay contends that the
ourt has no jurisdiction over those matters and that, in any event, the
 ims are not established on the merits.

 264. With respect to noise and visual pollution, the Court has already
ncluded in paragraph 52 that it has no jurisdiction on such matters
 der the 1975 Statute. As regards air pollution, the Court is of the view
at if emissions from the plant’s stacks have deposited into the aquatic
vironment substances with harmful effects, such indirect pollution of
e river would fall under the provisions of the 1975 Statute. Uruguay
 pears to agree with this conclusion. Nevertheless, in view of the find-
gs of the Court with respect to water quality, it is the opinion of the
ourt that the record does not show any clear evidence that substances
th harmful effects have been introduced into the aquatic environment
 the river through the emissions of the Orion (Botnia) mill into the air.

(f) Conclusions on Article 41
265. It follows from the above that there is no conclusive evidence in
e record to show that Uruguay has not acted with the requisite degree
 due diligence or that the discharges of effluent from the Orion (Botnia)
ll have had deleterious effects or caused harm to living resources or to
e quality of the water or the ecological balance of the river since it
 rted its operations in November 2007. Consequently, on the basis of
e evidence submitted to it, the Court concludes that Uruguay has not
eached its obligations under Article 41.

(g) Continuing obligations : monitoring
266. The Court is of the opinion that both Parties have the obligation
 enable CARU, as the joint machinery created by the 1975 Statute, to
ercise on a continuous basis the powers conferred on it by the 1975 Stat-
e, including its function of monitoring the quality of the waters of the
 er and of assessing the impact of the operation of the Orion (Botnia)
 ll on the aquatic environment. Uruguay, for its part, has the obligation
  continue monitoring the operation of the plant in accordance with
 ticle 41 of the Statute and to ensure compliance by Botnia with Uru-
 ayan domestic regulations as well as the standards set by CARU. The
 rties have a legal obligation under the 1975 Statute to continue their
-operation through CARU and to enable it to devise the necessary
eans to promote the equitable utilization of the river, while protecting
  environment.

                                  * *
                                                                         91

                V. THE CLAIMS MADE BY THE PARTIES
                    IN THEIR FINAL SUBMISSIONS

267. Having concluded that Uruguay breached its procedural obliga-
 ns under the 1975 Statute (see paragraphs 111, 122, 131, 149, 157 and
8 above), it is for the Court to draw the conclusions following from
ese internationally wrongful acts giving rise to Uruguay’s international
 ponsibility and to determine what that responsibility entails.

268. Argentina first requests the Court to find that Uruguay has vio-
 ed the procedural obligations incumbent on it under the 1975 Statute
d has thereby engaged its international responsibility. Argentina further
quests the Court to order that Uruguay immediately cease these inter-
tionally wrongful acts.
269. The Court considers that its finding of wrongful conduct by Uru-
ay in respect of its procedural obligations per se constitutes a measure
  satisfaction for Argentina. As Uruguay’s breaches of the procedural
 ligations occurred in the past and have come to an end, there is no
use to order their cessation.

 270. Argentina nevertheless argues that a finding of wrongfulness
ould be insufficient as reparation, even if the Court were to find that
 uguay has not breached any substantive obligation under the 1975 Stat-
e but only some of its procedural obligations. Argentina maintains that
e procedural obligations and substantive obligations laid down in the
 75 Statute are closely related and cannot be severed from one another
r purposes of reparation, since undesirable effects of breaches of the
rmer persist even after the breaches have ceased. Accordingly, Argen-
 a contends that Uruguay is under an obligation to “re-establish on the
ound and in legal terms the situation that existed before [the] interna-
 nally wrongful acts were committed”. To this end, the Orion
 otnia) mill should be dismantled. According to Argentina, restitutio in
 egrum is the primary form of reparation for internationally wrongful
ts. Relying on Article 35 of the International Law Commission’s
 ticles on the Responsibility of States for Internationally Wrongful Acts,
 gentina maintains that restitution takes precedence over all other forms
  reparation except where it is “materially impossible” or involves
  burden out of all proportion to the benefit deriving from restitution
 tead of compensation”. It asserts that dismantling the mill is not mat-
 ally impossible and would not create for the Respondent State a
 rden out of all proportion, since the Respondent has

   “maintained that construction of the mills would not amount to a
   fait accompli liable to prejudice Argentina’s rights and that it was
   for Uruguay alone to decide whether to proceed with construction

                                                                       92

  and thereby assume the risk of having to dismantle the mills in the
  event of an adverse decision by the Court”,

 the Court noted in its Order on Argentina’s request for the indication
  provisional measures in this case (Order of 13 July 2006, I.C.J.
 ports 2006, p. 125, para. 47). Argentina adds that whether or not
 titution is disproportionate must be determined at the latest as of the
ng of the Application instituting proceedings, since as from that time
 uguay, knowing of Argentina’s request to have the work halted and
e status quo ante re-established, could not have been unaware of the
k it ran in proceeding with construction of the disputed mill. Lastly,
 gentina considers Articles 42 and 43 of the 1975 Statute to be inappli-
ble in the present case, since they establish a régime of responsibility in
e absence of any wrongful act.

271. Taking the view that the procedural obligations are distinct from
e substantive obligations laid down in the 1975 Statute, and that
count must be taken of the purport of the rule breached in determining
e form to be taken by the obligation of reparation deriving from its
olation, Uruguay maintains that restitution would not be an appropri-
e form of reparation if Uruguay is found responsible only for breaches
  procedural obligations. Uruguay argues that the dismantling of the
 ion (Botnia) mill would at any rate involve a “striking disproportion
tween the gravity of the consequences of the wrongful act of which it is
cused and those of the remedy claimed”, and that whether or not a dis-
oportionate burden would result from restitution must be determined
 of when the Court rules, not, as Argentina claims, as of the date it was
 sed. Uruguay adds that the 1975 Statute constitutes a lex specialis in
 ation to the law of international responsibility, as Articles 42 and 43
 ablish compensation, not restitution, as the appropriate form of repa-
 ion for pollution of the river in contravention of the 1975 Statute.

 272. The Court, not having before it a claim for reparation based on a
gime of responsibility in the absence of any wrongful act, deems it
 necessary to determine whether Articles 42 and 43 of the 1975 Statute
 ablish such a régime. But it cannot be inferred from these Articles,
hich specifically concern instances of pollution, that their purpose or
 ect is to preclude all forms of reparation other than compensation for
eaches of procedural obligations under the 1975 Statute.

273. The Court recalls that customary international law provides for
 titution as one form of reparation for injury, restitution being the
establishment of the situation which existed before occurrence of the
ongful act. The Court further recalls that, where restitution is materi-
y impossible or involves a burden out of all proportion to the benefit
riving from it, reparation takes the form of compensation or satisfac-
n, or even both (see Gabčíkovo-Nagymaros Project (Hungary/Slovakia),

                                                                        93

dgment, I.C.J. Reports 1997, p. 81, para. 152 ; Legal Consequences
 the Construction of a Wall in the Occupied Palestinian Territory,
 visory Opinion, I.C.J. Reports 2004 (I), p. 198, paras. 152-153 ;
 plication of the Convention on the Prevention and Punishment of the
ime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro),
dgment, I.C.J. Reports 2007 (I), p. 233, para. 460 ; see also Articles 34
37 of the International Law Commission Articles on the Responsibil-
 of States for Internationally Wrongful Acts).

274. Like other forms of reparation, restitution must be appropriate to
e injury suffered, taking into account the nature of the wrongful act
ving caused it. As the Court has made clear,
   “[w]hat constitutes ‘reparation in an adequate form’ clearly varies
   depending upon the concrete circumstances surrounding each case
   and the precise nature and scope of the injury, since the question has
   to be examined from the viewpoint of what is the ‘reparation in an
   adequate form’ that corresponds to the injury” (Avena and Other
   Mexican Nationals (Mexico v. United States of America), Judg-
   ment, I.C.J. Reports 2004 (I), p. 59, para. 119).
275. As the Court has pointed out (see paragraphs 154 to 157 above),
e procedural obligations under the 1975 Statute did not entail any
suing prohibition on Uruguay’s building of the Orion (Botnia) mill,
 ling consent by Argentina, after the expiration of the period for nego-
 tion. The Court has however observed that construction of that mill
gan before negotiations had come to an end, in breach of the proce-
 ral obligations laid down in the 1975 Statute. Further, as the Court has
und, on the evidence submitted to it, the operation of the Orion (Bot-
a) mill has not resulted in the breach of substantive obligations laid
 wn in the 1975 Statute (paragraphs 180, 189 and 265 above). As Uru-
ay was not barred from proceeding with the construction and opera-
 n of the Orion (Botnia) mill after the expiration of the period for
gotiation and as it breached no substantive obligation under the
75 Statute, ordering the dismantling of the mill would not, in the view
 the Court, constitute an appropriate remedy for the breach of proce-
 ral obligations.

 276. As Uruguay has not breached substantive obligations arising
 der the 1975 Statute, the Court is likewise unable, for the same rea-
ns, to uphold Argentina’s claim in respect of compensation for alleged
 uries suffered in various economic sectors, specifically tourism and
 riculture.
 277. Argentina further requests the Court to adjudge and declare that
  uguay must “provide adequate guarantees that it will refrain in future
om preventing the Statute of the River Uruguay of 1975 from being
 plied, in particular the consultation procedure established by Chap-
   II of that Treaty”.

                                                                      94

278. The Court fails to see any special circumstances in the present
se requiring the ordering of a measure such as that sought by Argen-
 a. As the Court has recently observed :
      “[W]hile the Court may order, as it has done in the past, a State
   responsible for internationally wrongful conduct to provide the
   injured State with assurances and guarantees of non-repetition, it
   will only do so if the circumstances so warrant, which it is for the
   Court to assess.
      As a general rule, there is no reason to suppose that a State whose
   act or conduct has been declared wrongful by the Court will repeat
   that act or conduct in the future, since its good faith must be pre-
   sumed (see Factory at Chorzów, Merits, Judgment No. 13, 1928,
   P.C.I.J., Series A, No. 17, p. 63 ; Nuclear Tests (Australia v. France),
   Judgment, I.C.J. Reports 1974, p. 272, para. 60 ; Nuclear Tests
   (New Zealand v. France), Judgment, I.C.J. Reports 1974, p. 477,
   para. 63 ; and Military and Paramilitary Activities in and against
   Nicaragua (Nicaragua v. United States of America), Jurisdiction
   and Admissibility, Judgment, I.C.J. Reports 1984, p. 437, para. 101).
   There is thus no reason, except in special circumstances . . . to order
   [the provision of assurances and guarantees of non-repetition].”
   (Dispute regarding Navigational and Related Rights (Costa Rica v.
   Nicaragua), Judgment, I.C.J. Reports 2009, p. 267, para. 150.)
279. Uruguay, for its part, requests the Court to confirm its right “to
ntinue operating the Botnia plant in conformity with the provisions of
e 1975 Statute”. Argentina contends that this claim should be rejected,
 particular because it is a counter-claim first put forward in Uruguay’s
 joinder and, as such, is inadmissible by virtue of Article 80 of the
ules of Court.
280. There is no need for the Court to decide the admissibility of this
 im ; it is sufficient to observe that Uruguay’s claim is without any prac-
al significance, since Argentina’s claims in relation to breaches by Uru-
 ay of its substantive obligations and to the dismantling of the Orion
otnia) mill have been rejected.

                                 * * *
281. Lastly, the Court points out that the 1975 Statute places the
 rties under a duty to co-operate with each other, on the terms therein
  out, to ensure the achievement of its object and purpose. This obliga-
 n to co-operate encompasses ongoing monitoring of an industrial
cility, such as the Orion (Botnia) mill. In that regard the Court notes
at the Parties have a long-standing and effective tradition of co-opera-
 n and co-ordination through CARU. By acting jointly through CARU,
e Parties have established a real community of interests and rights in
e management of the River Uruguay and in the protection of its envi-
nment. They have also co-ordinated their actions through the joint

                                                                        95

echanism of CARU, in conformity with the provisions of the 1975 Stat-
e, and found appropriate solutions to their differences within its frame-
ork without feeling the need to resort to the judicial settlement of
 putes provided for in Article 60 of the Statute until the present case
 s brought before the Court.

                                 * * *
282. For these reasons,
THE COURT,
(1) By thirteen votes to one,
Finds that the Eastern Republic of Uruguay has breached its proce-
ral obligations under Articles 7 to 12 of the 1975 Statute of the River
uguay and that the declaration by the Court of this breach constitutes
propriate satisfaction ;
 N FAVOUR : Vice-President Tomka, Acting President ; Judges Koroma, Al-
  Khasawneh, Simma, Abraham, Keith, Sepúlveda-Amor, Bennouna, Skot-
  nikov, Cançado Trindade, Yusuf, Greenwood ; Judge ad hoc Vinuesa ;

AGAINST : Judge ad hoc Torres Bernárdez ;

(2) By eleven votes to three,
Finds that the Eastern Republic of Uruguay has not breached its sub-
 ntive obligations under Articles 35, 36 and 41 of the 1975 Statute of
e River Uruguay ;
 N FAVOUR : Vice-President Tomka, Acting President ; Judges Koroma, Abra-
  ham, Keith, Sepúlveda-Amor, Bennouna, Skotnikov, Cançado Trindade,
  Yusuf, Greenwood ; Judge ad hoc Torres Bernárdez ;

AGAINST : Judges Al-Khasawneh, Simma ; Judge ad hoc Vinuesa ;

(3) Unanimously,
Rejects all other submissions by the Parties.

 Done in French and in English, the French text being authoritative, at
e Peace Palace, The Hague, this twentieth day of April, two thousand
 d ten, in three copies, one of which will be placed in the archives of the
ourt and the others transmitted to the Government of the Argentine
 public and the Government of the Eastern Republic of Uruguay,
 pectively.

igned) Vice-President.                      (Signed) Peter TOMKA,
                                                    Vice-President.
                                         (Signed) Philippe COUVREUR,
                                                       Registrar.

                                                                        96

 Judges AL-KHASAWNEH and SIMMA append a joint dissenting opinion
  the Judgment of the Court ; Judge KEITH appends a separate opinion
 the Judgment of the Court ; Judge SKOTNIKOV appends a declaration to
e Judgment of the Court ; Judge CANÇADO TRINDADE appends a
parate opinion to the Judgment of the Court ; Judge YUSUF appends a
claration to the Judgment of the Court ; Judge GREENWOOD appends a
parate opinion to the Judgment of the Court ; Judge ad hoc
 RRES BERNÁRDEZ appends a separate opinion to the Judgment of the
ourt ; Judge ad hoc VINUESA appends a dissenting opinion to the Judg-
ent of the Court.

                                                  (Initialled) P.T.
                                                 (Initialled) Ph.C.

                                                                  97