13 December 1999

 

General List No. 98

 
     

international Court of Justice

     
 

Kasikili/Sedudu Island

 
     

Botswana

 

v. 

Namibia

     
     
 

Judgment

 
     
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BEFORE:

President: Schwebel;
Vice-President: Weeramantry;
Judges: Oda, Bedjaoui, Guillaume, Ranjeva, Herczegh, Shi, Fleischhauer, Koroma, Vereshchetin, Higgins, Parra-Aranguren, Kooijmans, Rezek

   
PermaLink: http://www.worldcourts.com/icj/eng/decisions/1999.12.13_kasikili.htm
   
Citation: Kasikili/Sedudu Island (Bots. v. Namib.), 1999 I.C.J. 1045 (Dec. 13)
   
Represented By: Botswana: Mr. Abednego Batshani Tafa, Advocate of the High Court and Court of Appeal of Botswana, Deputy Attorney-General, as Agent, Counsel and Advocate;
H.E. Mr. S. C. George, Ambassador of the Republic of Botswana to the European Union, Brussels, as Co-Agent;
Mr. Molosiwa L. Selepeng, Permanent Secretary for Political Affairs, Office of the President;
Professor Ian Brownlie, C.B.E., Q.C., F.B.A., Chichele Professor of Public International Law, University of Oxford, Member of the International Law Commission, Member of the English Bar, Member of the Institut de droit international;
Lady Fox Q.C., former Director of the British Institute of International and Comparative Law, Member of the English Bar, Associate Member of the Institut de droit international;
Dr. Stefan Talmon, Rechtsassessor, D. Phil. (Oxon), LL.M. (Cantab), Wissenschaftlicher Assistent in the Law Faculty of the University of Tubingen, as Counsel and Advocates;
Mr. Timothy Daniel, Solicitor of the Supreme Court; Partner, D. J. Freeman (Solicitors) of the City of London;
Mr. Alan Perry, Solicitor of the Supreme Court; Partner, D. J. Freeman (Solicitors) of the City of London;
Mr. David Lerer, Solicitor of the Supreme Court; Assistant, D. J. Freeman (Solicitors) of the City of London;
Mr. Christopher Hackford, Solicitor of the Supreme Court; Assistant, D. J. Freeman (Solicitors) of the City of London;
Mr. Robert Paydon, Solicitor of the Supreme Court; Assistant, D. J. Freeman (Solicitors) of the City of London, as Counsel;
Professor F. T. K. Sefe, Professor of Hydrology, Department of Environmental Science, University of Botswana, Gaborone;
Mr. Isaac Muzila, B. Sc. Civil Engineering, Principal Hydrological Engineer, Department of Water Affairs, Botswana;
Mr. Alan Simpkins, F.R.I.C.S., Prof. M.I.T.E.S. (S.A.), L.S. (Bots.); Chief Surveyor and Deputy to Director, Department of Surveys and Mapping, Botswana;
Mr. Scott B. Edmonds, Director of Cartographic Operations, GeoSystems Global Corporation, Columbia, Maryland (United States of America);
Mr. Robert C. Rizzutti, Senior Mapping Specialist, GeoSystems Global Corporation, Columbia, Maryland (United States of America);
Mr. Justin E. Morrill, Senior Multimedia Designer, GeoSystems Global Corporation, Columbia, Maryland (United States of America),
as Scientific and Technical Advisers;
Mr. Bapasi Mphusu, Chief Press Officer, Department of Information and Broadcasting, Government of Botswana, as Information Adviser;
Mrs. Coralie Ayad, D. J. Freeman (Solicitors) of the City of London;
Mrs. Marilyn Beeson, D. J. Freeman (Solicitors) of the City of London;
Ms Michelle Burgoine, D. J. Freeman (Solicitors) of the City of London, as Administrators;

Namibia: Dr. Albert Kawana, Permanent Secretary, Ministry of Justice of Namibia, as Agent, Counsel and Advocate;
H.E. Dr. Zedekia J. Ngavirue, Ambassador of the Republic of Namibia to the Netherlands, as Deputy-Agent;
Professor Abram Chayes, Felix Frankfurter Professor of Law Emeritus, Harvard Law School;
Professor Sir Elihu Lauterpacht, C.B.E., Q.C., Honorary Professor of International Law, University of Cambridge, Member of the Institut de droit international;
Mr. Jean-Pierre Cot, Professor Emeritus, Universite de Paris I (Pantheon-Sorbonne), Member of the Paris and Brussels Bars, Vice-President of the European Parliament;
Professor Dr. Jost Delbruck, Director of Walther-Schucking Institute of International Law, University of Kiel;
Professor Dr. Julio Faundez, Professor of Law, University of Warwick,
as Counsel and Advocates;
Professor W. J. R. Alexander, Emeritus Professor of Hydrology, University of Pretoria;
Professor Keith S. Richards, Department of Geography, University of Cambridge;
Colonel Dennis Rushworth, Former Director of the Mapping and Charting Establishment, Ministry of Defence of the United Kingdom,
Dr. Lazarus Hangula, Director, Multidisciplinary Research Centre, University of Namibia, as Advocates;
Dr. Arnold M. Mtopa, Chief Legal Officer, Ministry of Justice of Namibia;
Dr. Collins Parker, Chief Legal Officer, Ministry of Justice of Namibia,
Mr. Edward Helgeson, Fellow, Lauterpacht Research Centre for International Law, University of Cambridge;
Ms Tonya Putnam, Harvard Law School, as Counsel and Advisers;
Mr. Peter Clark, Former Chief Map Research Officer, Ministry of Defence, United Kingdom, as Technical Adviser;
Mr. Samson N. Muhapi, Special Assistant to the Permanent Secretary, Ministry of Justice of Namibia;
Ms Kyllikki M. Shaduka, Private Secretary, Ministry of Justice of Namibia;
Ms Mercia G. Louw, Private Secretary, Ministry of Justice of Namibia,
as Administrative staff;
Mr. Peter Denk, Reporter;
Mr. Muyenga Muyenga, Reporter, as Information Advisers.

 
     
 
 
     
 

[p1045]
The Court,

composed as above,

after deliberation,

delivers the following Judgment:

1. By joint letter dated 17 May 1996, filed in the Registry of the Court on 29 May 1996, the Ministers for Foreign Affairs of the Republic of Botswana (hereinafter called "Botswana") and the Republic of Namibia (hereinafter called "Namibia") transmitted to the Registrar the original text of a Special [p1049] Agreement between the two States, signed at Gaborone on 15 February 1996 and entered into force on 15 May 1996, the date of exchange of instruments of ratification.

2. The text of the Special Agreement reads as follows:

"Whereas a Treaty between Great Britain and Germany respecting the spheres of influence of the two countries in Africa was signed on 1 July 1890 (the Anglo-German Agreement of 1890);

Whereas a dispute exists between the Republic of Botswana and the Republic of Namibia relative to the boundary around Kasikili/Sedudu Island;

Whereas the two countries are desirous of settling such dispute by peaceful means in accordance with the principles of both the Charter of the United Nations and the Charter of the Organization of African Unity;

Whereas the two countries appointed on 24 May 1992 a Joint Team of Technical Experts on the Boundary between Botswana and Namibia around Kasikili/Sedudu Island 'to determine the boundary between Namibia and Botswana around Kasikili/Sedudu Island' on the basis of the Treaty of 1 July 1890 between Great Britain and Germany respecting the spheres of influence of the two countries in Africa and the applicable principles of international law;

Whereas the Joint Team of Technical Experts was unable to reach a conclusion on the question referred to it and recommended 'recourse to the peaceful settlement of the dispute on the basis of the applicable rules and principles of international law';

Whereas at the Summit Meeting held in Harare, Zimbabwe, on 15 February 1995, and attended by Their Excellencies President Sir Ketumile Masire of Botswana, President Sam Nujoma of Namibia and President Robert Mugabe of Zimbabwe, the Heads of State of the Republic of Botswana and the Republic of Namibia, acting on behalf of their respective Governments, agreed to submit the dispute to the International Court of Justice for a final and binding determination;

Now therefore the Republic of Botswana and the Republic of Namibia have concluded the following Special Agreement:

Article I

The Court is asked to determine, on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law, the boundary between Namibia and Botswana around Kasikili/Sedudu Island and the legal status of the island.

Article II

1. The proceedings shall consist of written pleadings and oral hearings.

2. The written pleadings shall include:

(a) Memorials submitted to the Court by each Party not later than nine months after the notification of the Special Agreement is transmitted [p1050] to the Registrar of the Court in accordance with Article VII (2) of this Special Agreement;

(b) Counter-Memorials submitted by each Party to the Court not later than nine months after the date of submission of the Memorials;

(c) such other written pleadings as may be approved by the Court at the request of either of the Parties, or as may be directed by the Court.

3. The written pleadings submitted to the Registrar shall not be communicated to the other Party until the corresponding pleadings of that Party have been received by the Registrar.

Article III

The rules and principles of international law applicable to the dispute shall be those set forth in the provisions of Article 38, paragraph 1, of the Statute of the International Court of Justice.

Article IV

The order of appearance in the oral pleadings shall be as agreed by the Parties with the approval of the Court, or in the absence of agreement, as directed by the Court.

Article V

The order of the written pleadings and oral submissions shall be without prejudice to the burden of proof.

Article VI

The language of the proceedings shall be English.

Article VII

1. This agreement shall enter into force on the date of the exchange of instruments of ratification by the two Governments.

2. It shall be notified to the Court as required by Article 40, paragraph 3, of the Statute of the Court by joint letter of the Parties to the Registrar.

3. If such notification is not effected within two months from the entry into force of this Special Agreement, it may be notified to the Registrar by either of the Parties.

Article VIII

1. Each of the Parties may exercise its right under Article 31, paragraph 3, of the Statute of the Court to choose a person to sit as judge.

2. A Party which chooses to exercise the right referred to in sub-Article 1, above, shall notify the other Party in writing prior to exercising such right.

Article IX

1. The judgment of the Court on the dispute described in Article I shall be final and binding on the Parties.

2. As soon as possible after the delivery of the Court's judgment, the Parties shall take steps necessary to carry out the judgment. [p1051]

In witness whereof, the undersigned, being duly authorized thereto, have signed this Special Agreement and have affixed thereto their seals."


3. Pursuant to Article 40, paragraph 3, of the Statute and Article 42 of the Rules of Court, copies of the notification and of the Special Agreement were transmitted by the Registrar to the Secretary-General of the United Nations, the Members of the United Nations and other States entitled to appear before the Court.

4. By Order of 24 June 1996, the Court fixed 28 February 1997 as the time-limit for the filing of a Memorial by each Party and 28 November 1997 as the time-limit for the filing by each Party of a Counter-Memorial, having regard to the provisions of Article II, paragraph 2 (a) and (b), of the Special Agreement. These pleadings were duly filed within the time-limits so prescribed.

5. By Order of 27 February 1998, the Court fixed 27 November 1998 as the time-limit for the filing of a Reply by each Party, having regard to the provisions of Article II, paragraph 2 (c), of the Special Agreement and taking account of the agreement between the Parties, as expressed in a joint letter from their Agents dated 16 February 1998. The Replies were duly filed within the time-limit so prescribed. As the Parties did not request the submission of other pleadings, and as the Court itself did not consider this necessary, the case was then ready for hearing.

6. In accordance with Article 53, paragraph 2, of the Rules of Court, the Court decided, after having ascertained the views of the Parties, that copies of the pleadings and documents annexed would be made available to the public as from the opening of the oral proceedings.

7. New documents were produced by each of the Parties, with the consent of the other, in accordance with Article 56, paragraph 1, of the Rules of Court. In addition, Namibia, availing itself of the right provided for in Article 56, paragraph 3, of the Rules of Court, submitted comments on certain of the new documents produced by Botswana.

8. The Parties having been duly consulted, in accordance with Article 58, paragraph 2, of the Rules of Court, and having informed the Court of their agreement, in accordance with Article IV of the Special Agreement, on the order of speaking, public sittings were held between 15 February and 5 March 1999, during which oral arguments and replies were heard from the following:

For Namibia: Dr. Albert Kawana,
Professor Abram Chayes,
Professor Dr. Jost Delbruck,
Professor W. J. R. Alexander,
Dr. Lazarus Hangula,
Professor Dr. Julio Faundez,
Colonel Dennis Rushworth,
Mr. Jean-Pierre Cot.

For Botswana: Mr. Abednego Batshani Tafa,
Mr. Molosiwa L. Selepeng,
Professor Ian Brownlie,
Lady Fox,
Dr. Stefan Talmon,
Professor F. T. K. Sefe,
Mr. Isaac Muzila.

[p1052]
At the sittings, each of the Parties showed a video cassette, after those cassettes had been exchanged between the Parties through the intermediary of the Registry.

Questions were also put by Members of the Court, to which both Parties replied in writing, within the time-limit fixed for this purpose.

9. In the course of the written proceedings, the following submissions were presented by the Parties:

On behalf of Botswana,

in the Memorial, the Counter-Memorial and the Reply:

"May it please the Court to adjudge and declare that:

1. The northern and western channel of the Chobe River in the vicinity of Kasikili/Sedudu Island constitutes the 'main channel' of the Chobe River in accordance with the provisions of Article III (2) of the Anglo-German Agreement of 1890; and that:

2. Consequently, sovereignty in respect of Kasikili/Sedudu Island inheres exclusively in the Republic of Botswana."

On behalf of Namibia,

in the Memorial and the Counter-Memorial:

"May it please the Court, rejecting all claims and submissions to the contrary, to adjudge and declare:

1. The channel that lies to the south of Kasikili/Sedudu Island is the main channel of the Chobe River.

2. The channel that lies to the north of Kasikili/Sedudu Island is not the main channel of the Chobe River.

3. Namibia and its predecessors have occupied and used Kasikili Island and exercised sovereign jurisdiction over it, with the knowledge and acquiescence of Botswana and its predecessors since at least 1890.

4. The boundary between Namibia and Botswana around Kasikili/Sedudu Island lies in the centre of the southern channel of the Chobe River.

5. The legal status of Kasikili/Sedudu Island is that it is a part of the territory under the sovereignty of Namibia."

In the Reply:

"May it please the Court, rejecting all claims and submissions to the contrary, to adjudge and declare

1. The channel that lies to the south of Kasikili/Sedudu Island is the main channel of the Chobe River.

2. The channel that lies to the north of Kasikili/Sedudu Island is not the main channel of the Chobe River.

3. Namibia and its predecessors have occupied and used Kasikili Island and exercised sovereign jurisdiction over it, with the knowledge and acquiescence of Botswana and its predecessors since at least 1890.

4. The boundary between Namibia and Botswana around Kasikili/Sedudu Island lies in the centre (that is to say, the thalweg) of the southern channel of the Chobe River. [p1053]

5. The legal status of Kasikili/Sedudu Island is that it is a part of the territory under the sovereignty of Namibia."


10. In the oral proceedings, the following submissions were presented by the Parties:

On behalf of Botswana,

at the hearing of 5 March 1999:

"May it please the Court:

(1) to adjudge and declare:

(a) that the northern and western channel of the Chobe River in the vicinity of Kasikili/Sedudu Island constitutes the 'main channel' of the Chobe River in accordance with the provisions of Article III (2) of the Anglo-German Agreement of 1890; and

(b) consequently, sovereignty in respect of Kasikili/Sedudu Island vests exclusively in the Republic of Botswana; and further

(2) to determine the boundary around Kasikili/Sedudu Island on the basis of the thalweg in the northern and western channel of the Chobe River.”

On behalf of Namibia,

at the hearing of 2 March 1999:

***

The submissions read at the hearing were identical to those presented by Namibia in the Reply.

11. The Parties, in the terms of the Special Agreement, request the Court, "to determine, on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law, the boundary between Namibia and Botswana around Kasikili/Sedudu Island and the legal status of the island." The Island referred to, which in Namibia is known as "Kasikili", and in Botswana as "Sedudu", is approximately 3.5 square kilometres (1.5 square miles) in area. It is located in the Chobe River, which divides around it to the north and south, in the area bounded approximately by meridians 25 [degree] 07' and 25 [degree] 08' E longitude and parallels 17 [degree] 47' and 17 [degree] 50' S latitude, and is some 20 kilometres (12.5 miles) upstream of Kazungula where the Chobe flows into the Zambezi. The Chobe has its source on the central plateau of Angola, where it is called the Rio Cuando. It undergoes further changes of name at various stages along its course. When it crosses the border into Namibia, it becomes the Kwando and then the Mashi, which flows generally in a southerly direction into the Linyanti (or Linyandi) Swamp. From this point it is called the Linyanti (or Linyandi) River until it reaches Lake Liambezi. At the exit from the lake, the river becomes the Chobe. The Botswana town of Kasane lies on the south bank some 1.5 kilometres downstream from Kasikili/Sedudu Island, and the Namibian village of Kasika is located on the northwestern bank of the Chobe.

12. Nearly due south of the Island, on the Botswana side, are the [p1054] headquarters of the Chobe National Park, a protected reserve with a wide variety of wildlife. This southern bank is characterized by a steep sandy ridge ranging between 900 and 1,000 metres above mean sea level. The area on the Namibian side, to the north of the Island, has no such geographical feature. It forms part of a strip of territory called the "Caprivi Strip", after the German chancellor at the time of the conclusion of the Anglo-German Agreement of 1 July 1890 (hereinafter the "1890 Treaty"). This part of the Caprivi Strip is within the seasonal flood plain of the Zambezi River. The Island, which is 927 metres above mean sea level, forms part of this plain, and is subject to flooding of several months' duration, beginning around March. In order to assist in the reading of this Judgment, the Court has included below three sketch-maps, the first illustrating the position of Botswana and Namibia on the continent of Africa (Sketch-map No. 1); the second showing the Caprivi Strip and the Chobe (Sketch-map No. 2); and the third showing Kasikili/Sedudu Island (Sketch-map No. 3).

13. The dispute between the Parties is set against the background of the nineteenth century race among the European colonial powers for the partition of Africa. In the spring of 1890, Germany and Great Britain entered into negotiations with a view to reaching agreement concerning their trade and their spheres of influence in Africa. In the south-west of the continent, Great Britain sought to protect the south-north trade routes running through Lake Ngami to Victoria Falls, while Germany, which had already laid claim to a large portion of what was called "South West Africa", sought British recognition of its access to the Zambezi. These negotiations culminated in the conclusion of the 1890 Treaty, which concerned several regions of the African continent, namely east Africa, south-west Africa, Togo and Zanzibar, and involved the cession to Germany of the island of Heligoland, in exchange for Zanzibar. The Treaty delimited inter alia the spheres of influence of Germany and Great Britain in south-west Africa; that delimitation lies at the heart of the present case.

14. In the ensuing century, the territories involved experienced various mutations in status. The independent Republic of Botswana came into being on 30 September 1966, on the territory of the former British Bechuanaland Protectorate. German administration of South West Africa turned out to be short-lived. Upon the outbreak of the First World War in 1914, the Caprivi Strip was occupied and governed by British forces from Southern Rhodesia. From 1919 until 1966, South Africa was the administering authority of the territory of South West Africa under a mandate from the League of Nations. For part of this period, from 1921 to 1929, South Africa delegated the administration of the Caprivi Strip to the authorities of the British Bechuanaland Protectorate. South Africa's mandate over South West Africa was terminated by the United Nations General Assembly in 1966, following which the Assembly established a

[p1055]

Sketch-Map No. 1

[p1056]

[Map]

[p1057]

Sketch-Map No. 3

[p1058] United Nations Council for South West Africa (which subsequently became the United Nations Council for Namibia), which it designated as the authority responsible for the administration of Namibia; but South Africa remained in de facto control of the territory, despite United Nations policy to the contrary, until Namibia's independence on 21 March 1990.

15. Shortly after Namibian independence, differences arose between the two States concerning the location of the boundary around Kasikili/Sedudu Island. When the two Parties proved unable to resolve their dispute, they called upon the good offices of the President of Zimbabwe. His efforts led to a meeting of the Presidents of the three countries at Kasane, Botswana, in May 1992, at which they issued a communique, declaring that the issue should be resolved peacefully, and recording the Presidents' agreement to submit the determination of the boundary around Kasikili/Sedudu Island to a Joint Team of Technical Experts. Terms of reference for the Joint Team were agreed between the parties in December 1992, and the Joint Team conducted its survey between September 1993 and August 1994. In its final Report, issued on 20 August 1994, the Joint Team announced that it had failed to reach an agreed conclusion on the question put to it, and recommended recourse to the peaceful settlement of the dispute on the basis of the applicable rules and principles of international law.

16. In February 1995, the three Presidents met in Harare, Zimbabwe, to consider the Joint Team Report. At this meeting, it was decided to submit the dispute to the International Court of Justice for a final and binding determination. Pursuant to this decision, Botswana and Namibia, by a Special Agreement signed at Gaborone on 15 February 1996, brought the dispute before the Court.

***


17. The Court recalls that according to Article I of the Special Agreement, it:

"is asked to determine, on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law, the boundary between Namibia and Botswana around Kasikili/Sedudu Island and the legal status of the island".

Accordingly the Court has a dual task: to determine both the boundary between Botswana and Namibia around Kasikili/Sedudu Island and the legal status of the Island. For this purpose, the Court must base itself on the 1890 Treaty and on the rules and principles of international law.

*[p1059]

18. The law applicable to the present case has its source first of all in the 1890 Treaty, which Botswana and Namibia acknowledge to be binding on them.

As regards the interpretation of that Treaty, the Court notes that neither Botswana nor Namibia are parties to the Vienna Convention on the Law of Treaties of 23 May 1969, but that both of them consider that Article 31 of the Vienna Convention is applicable inasmuch as it reflects customary international law. The Court itself has already had occasion in the past to hold that customary international law found expression in Article 31 of the Vienna Convention (see Territorial Dispute (Libyan Arab Jamahiriya/Chad), Judgment, I.C.J. Reports 1994, p. 21, para. 41; Oil Platforms (Islamic Republic of Iran v. United States of America), Preliminary Objections, Judgment, I.C.J. Reports 1996 (II), p. 812, para. 23). Article 4 of the Convention, which provides that it "applies only to treaties which are concluded by States after the entry into force of the . . . Convention with regard to such States" does not, therefore, prevent the Court from interpreting the 1890 Treaty in accordance with the rules reflected in Article 31 of the Convention.

According to Article 31 of the Vienna Convention on the Law of Treaties:

"1. A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose.

2. The context for the purpose of the interpretation of a treaty shall comprise, in addition to the text, including its preamble and annexes:

(a) any agreement relating to the treaty which was made between all the parties in connection with the conclusion of the treaty;

(b) any instrument which was made by one or more parties in connection with the conclusion of the treaty and accepted by the other parties as an instrument related to the treaty."

19. The Special Agreement also refers, in Article I, to the "rules and principles of international law". Article III of the Special Agreement further states that these rules and principles "shall be those set forth in the provisions of Article 38, paragraph 1, of the Statute of the International Court of Justice". The Court will revert to the issue - in dispute between the parties - of whether this reference in the Special Agreement to the "rules and principles of international law" permits the Court to entertain Namibia's alternative argument founded on the doctrine of prescription (see paragraphs 90-94 below).

The Parties also refer to the principles of both the Charter of the United Nations and the Charter of the Organization of African Unity (OAU), as well as to esolution AHG/Res. 16 (1), adopted in Cairo on 21 July 1964 by the Assembly of Heads of State and Government of the OAU. The latter provides that Member States of the OAU pledge themselves inter alia to respect the frontiers existing on their achievement [p1060] of national independence (an implementation of the principle of uti possedetis juris).

***

20. The Court will now proceed to interpret the provisions of the 1890 Treaty by applying the rules of interpretation set forth in the 1969 Vienna Convention. It recalls that

"a treaty must be interpreted in good faith, in accordance with the ordinary meaning to be given to its terms in their context and in the light of its object and purpose. Interpretation must be based above all upon the text of the treaty. As a supplementary measure recourse may be had to means of interpretation such as the preparatory work of the treaty." (Territorial Dispute (Libyan Arab Jamahiriya/Chad), Judgment, I.C.J. Reports 1994, pp. 21-22, para. 41.)
In order to illuminate the meaning of words agreed upon in 1890, there is nothing that prevents the Court from taking into account the present-day state of scientific knowledge, as reflected in the documentary material submitted to it by the Parties (compare Controversia sobre el recorrido de la traza del limite entre el Hito 62 y el Monte Fitz Roy (Argentina/Chile) [Dispute concerning the course of the frontier between B.P. 62 and Mount Fitzroy (Argentina/Chile)], also known as the "Laguna del desierto" case, Arbitral Award of 21 October 1994, International Law Reports (ILR), Vol. 113, p. 76, para. 157; Revue generale de droit international public (RGDIP), Vol. 2, 1996, p. 592, para. 157).

21. The Court will first examine the text of the 1890 Treaty, Article III of which reads as follows:

"In Southwest Africa the sphere in which the exercise of influence is reserved to Germany is bounded:

1. To the south by a line commencing at the mouth of the Orange river, and ascending the north bank of that river to the point of its intersection by the 20th degree of east longitude.

2. To the east by a line commencing at the above-named point, and following the 20th degree of east longitude to the point of its intersection by the 22nd parallel of south latitude; it runs eastward along that parallel to the point of its intersection by the 21st degree of east longitude; thence it follows that degree northward to the point of its intersection by the 18th parallel of south latitude; it runs eastward along that parallel till it reaches the river Chobe, and descends the centre of the main channel of that river to its junction with the Zambesi, where it terminates.

It is understood that under this arrangement Germany shall have free access from her Protectorate to the Zambesi by a strip of territory which shall at no point be less than 20 English miles in width. [p1061]

The sphere in which the exercise of influence is reserved to Great Britain is bounded to the west and northwest by the above-mentioned line. It includes Lake Ngami.

The course of the above boundary is traced in general accordance with a map officially prepared for the British Government in 1889."

As far as the region covered by the present case is concerned, this provision locates the dividing line between the spheres of influence of the contracting parties in the "main channel" of the River Chobe; however, neither this, nor any other provision of the Treaty, furnishes criteria enabling that "main channel" to be identified. It must also be noted that the English version refers to the "centre" of the main channel, while the German version uses the term "thalweg" of that channel (Thalweg des Hauptlaufes).

22. Throughout the proceedings, the Parties have expressed differing opinions regarding the method to be applied for the purpose of interpreting these expressions.
Botswana contends that:

"in a bifurcated stretch of river, such as the Chobe River in the vicinity of Kasikili/Sedudu Island, both channels will have their respective thalwege. However, the thalweg of the main channel will be at a lower elevation than the thalweg of the other channel. Only the thalweg of the main channel can be logically connected to the thalweg of the channel upstream of the point of bifurcation and downstream of the point of reunion."

Botswana maintains that, in order to establish the line of the boundary around Kasikili/Sedudu Island, it is sufficient to determine the thalweg of the Chobe; it is that which identifies the main channel of the river. For Botswana, the words "des Hauptlaufes" therefore add nothing to the text.

23. For Namibia, however, the task of the Court is first to identify the main channel of the Chobe around Kasikili/Sedudu Island, and then to determine where the centre of this channel lies:

"The 'main channel' must be found first; the 'centre' can necessarily only be found afterward. This point is equally pertinent to the German translation of the formula '. . . im Thalweg des Hauptlaufes . . .' In the same way as with the English text, the search must first be for the 'Hauptlauf' and for the 'Thalweg' only after the 'Hauptlauf' has been found. The 'Hauptlauf' cannot be identified by first seeking to find the 'Thalweg'."


24. The Court notes that various definitions of the term "thalweg" are found in treaties delimiting boundaries and that the concepts of the thalweg of a watercourse and the centre of a watercourse are not equivalent. The word "thalweg" has variously been taken to mean "the most suitable channel for navigation" on the river, the line "determined by the line of [p1062] deepest soundings", or "the median line of the main channel followed by boatmen travelling downstream". Treaties or conventions which define boundaries in watercourses nowadays usually refer to the thalweg as the boundary when the watercourse is navigable and to the median line between the two banks when it is not, although it cannot be said that practice has been fully consistent.

25. The Court further notes that at the time of the conclusion of the 1890 Treaty, it may be that the terms "centre of the [main] channel" and "Thalweg" des Hauptlaufes were used interchangeably. In this respect, it is of interest to note that, some three years before the conclusion of the 1890 Treaty, the Institut de droit international stated the following in Article 3, paragraph 2, of the "Draft concerning the international regulation of fluvial navigation", adopted at Heidelberg on 9 September 1887: "The boundary of States separated by a river is indicated by the thalweg, that is to say, the median line of the channel" (Annuaire de l'Institut de droit international, 1887-1888, p. 182), the term "channel" being understood to refer to the passage open to navigation in the bed of the river, as is clear from the title of the draft. Indeed, the parties to the 1890 Treaty themselves used the terms "centre of the channel" and "thalweg" as synonyms, one being understood as the translation of the other (see paragraph 46 below).

The Court observes, moreover, that in the course of the proceedings, Botswana and Namibia did not themselves express any real difference of opinion on this subject. The Court will accordingly treat the words "centre of the main channel" in Article III, paragraph 2, of the 1890 Treaty as having the same meaning as the words "Thalweg des Hauptlaufes" (cf. 1969 Vienna Convention on the Law of Treaties, Article 33, paragraph 3, under which "the terms of the treaty are presumed to have the same meaning in each authentic text").

26. The Court adds that, in this case, the Parties to the dispute have used the term "channel" to refer to each of the two branches of the Chobe that ring Kasikili/Sedudu Island, and have not confined the term "channel" to the stricter usage meaning the navigable passage of a river or of one of its branches. In view of this fact, the Court itself in this Judgment will likewise employ the term "channel" in a broad sense.

27. In the Court's opinion, the real dispute between the Parties concerns the location of the main channel where the boundary lies. In Botswana's view, it is to be found "on the basis of the thalwegs in the northern and western channel of the Chobe", whereas in Namibia's view, it "lies in the centre (that is to say thalweg) of the southern channel of the Chobe River".

While Botswana thought it sufficient for the Court to locate the line of deepest soundings in this section of the Chobe, which in its view leads to the centre of the northern channel as the boundary, the Court notes that this was not the only test it relied on. Moreover, the Court observes that by introducing the term "main channel" into the draft treaty, the con-[p1063]tracting parties must be assumed to have intended that a precise meaning be given to it. For these reasons, the Court will therefore proceed first to determine the main channel. In so doing, it will seek to determine the ordinary meaning of the words "main channel" by reference to the most commonly used criteria in international law and practice, to which the Parties have referred.

**

28. Before entering into an examination of these criteria, the Court observes that the Parties' experts have submitted to it extensive, often contradictory, information on the distinguishing features of the Chobe.

For Botswana, the Chobe "is a perennial river independent of the Zambezi River, with a stable profile, continuous downstream flow and visible and stable banks".

Namibia, for its part, claims that the Chobe cannot be regarded as a perennial river, and that in reality it is an ephemeral watercourse. Namibia points out that the Chobe is very often dry over a substantial section of its course, so that it is not navigable over most of its length.

The Court does not find itself charged with making findings on the distinguishing features of the Chobe River. It will take these into account only in so far as they affect the sector of Kasikili/Sedudu Island. The Court's task is in fact limited to settling the dispute between Botswana and Namibia by determining the boundary between these two States around the Island as well as the legal status of the Island.

29. The Parties to the dispute agree on many of the criteria for identifying the "main channel", but disagree on the relevance and applicability of several of those criteria.

For Botswana, the relevant criteria are as follows: greatest depth and width; bed profile configuration; navigability; greater flow of water. Botswana also lays stress, in the following terms, on the importance, from the standpoint of identification of the main channel, of "channel capacity", "flow velocity" and "volume of flow":

"channel capacity - This is determined by width and depth of the channel and in the discharge equation it is represented by cross-sectional area. From the cross-section survey and the analysis of satellite imagery, it is clear that the northern channel is deeper than the southern channel. . . .

flow velocity - Flow velocity is a function of bed slope, hydraulic radius and roughness coefficient. . . . the northern channel has a steeper bed slope; both of its banks are smooth (compared to the southern channel), therefore velocity will be higher in that channel.

volume of flow - Volume of flow in a channel is computed as the [p1064] product of channel capacity (cross-section area) and mean velocity through the cross-section."

Namibia acknowledges that

"possible criteria for identifying the main channel in a river with more than one channel are the channel with the greatest width, or the greatest depth, or the channel that carries the largest proportion of the annual flow of the river. In many cases the main channel will have all three of these characteristics."

It adds, however, referring to the sharp variations in the level of the Chobe's waters, that: "neither width nor depth are suitable criteria for determining which channel is the main channel."

Namibia nevertheless further states the following:

"Various criteria may be employed; these include width, depth, velocity, discharge, and sediment transport capacity. Since discharge is the product of width, mean depth and mean velocity, and is a determinant of transport capacity, it is the most straightforward and general criterion."

Among the possible criteria, Namibia therefore attaches the greatest weight to the amount of flow: according to Namibia, the main channel is the one "that carries the largest proportion of the annual flow of the river". Namibia also emphasized that another key task was to identify the channel that is "most used for river traffic".

30. The Court finds that it cannot rely on one single criterion in order to identify the main channel of the Chobe around Kasikili/Sedudu Island, because the natural features of a river may vary markedly along its course and from one case to another. The scientific works which define the concept of "main channel" frequently refer to various criteria: thus, in the Dictionnaire francais d'hydrologie de surface avec equivalents en anglais, espagnol, allemand (Masson, 1986), the "main channel" is "the widest, deepest channel, in particular the one which carries the greatest flow of water" (p. 66); according to the Water and Wastewater Control Engineering Glossary (Joint Editorial Board Representing the American Public Health Association, American Society of Civil Engineers, American Water Works Association and Water Pollution Control Federation, 1969), the "main channel" is "the middle, deepest or most navigable channel" (p. 197). Similarly, in the Rio Palena Arbitration, the arbitral tribunal appointed by the Queen of England applied several criteria in determining the major channel of a boundary river (Argentina-Chile Frontier Case (1966), United Nations, Reports of International Arbitral Awards (RIAA), Vol. XVI, pp. 177-180; International Law Reports (ILR), Vol. 38, pp. 94-98). The Court notes that the Parties have expressed their views on one or another aspect of the criteria mentioned in paragraph 29 above, distinguishing between them or placing emphasis [p1065] on their complementarity and their relationship with other criteria. It will take into account all of these criteria.

31. Before coming to a conclusion on the respective role and significance of the various criteria thus chosen, the Court notes, on the basis of the information supplied by both Parties concerning the hydrological situation of Kasikili/Sedudu Island, that there are compelling reasons for assuming that this situation has seen no radical change over the last hundred years. The aerial photographs taken in 1925, 1943, 1947, 1962, 1972, 1977, 1981 and 1985 show no major mutation in the channels of the Chobe and indicate that the channels surrounding the Island remained relatively stable throughout that period of time. Moreover, the Parties are in agreement on this point. Namibia states on this count:

"Namibia's position does not depend on any changes in the general configuration of the Island and the surrounding area since the Treaty was signed. Thus, Namibia accepts that there have been no significant changes in the location of the northern and southern channels since 1890."

Similarly, Botswana affirms that there

"is a complete absence of any evidence of radical change in the course of the Chobe. Large scale maps both before and after the 1890 Anglo-German Agreement, prepared by those who had actually surveyed this stretch of the Chobe River, show an unchanged course."

In short, the present hydrological situation of the Chobe around Kasikili/Sedudu Island may be presumed to be essentially the same as that which existed when the 1890 Treaty was concluded.

32. The Court will first examine the criterion of depth. According to Botswana's experts, the mean depth of the northern channel is 5.70 metres, clearly exceeding the mean depth of the southern channel by 2.13 metres. As for the shallowest points, the depth is said to be 1.5 to 2 metres at the entry to the southern channel, i.e., a much shallower depth than in the northern channel.

Although Namibia agrees that the northern channel has the greater mean depth, it disputes that this conclusion is of any importance whatsoever for determining the main channel. It maintains that what is important in this respect is not mean depth but draught at the shallowest point of the channel; and it asserts that any differences between the shallowest points in the northern and southern channels are minute. For Namibia, the results of the 1985 Joint Survey (see paragraph 64 below) in respect of the minimum depth of the two channels (see Reply of Namibia, Vol. II, Second supplementary report to the expert report on the identification of the main channel of the Chobe River at Kasikili Island, Fig. 14) are incon-[p1066]clusive, in so far as "the minimum thalweg depths of the two channels within the bifurcation zone were not determined" Namibia also introduced photographs showing a herd of elephants crossing the two channels of the Chobe, but produced no figures to show that the minimum depth of the southern channel was greater than that of the northern channel.

Notwithstanding all the difficulties involved in sounding the depth of the channels and interpreting the results, the Court concludes that the northern channel is deeper than the southern one as regards mean depth, and even as regards minimum depth.

33. The Court will now consider the criterion of width. The width of a river may increase or decrease in line with the variable level of its waters. In order to deal with this phenomenon, the width has often been determined on the basis of the low water mark (see, e.g., Article IX of the Boundary Convention between Baden and France of 30 January 1827 (De Clerq, Recueil des Traites de la France, Vol. III, pp. 429 et seq.); see also the judgment of the United States Supreme Court of 19 May 1933 in the case Vermont v. New Hampshire, United States Reports, Vol. 289, p. 619 (1933)) or the mean water level (see, e.g., the Arbitral Award rendered on 23 January 1933 by the Special Boundary Tribunal constituted by the Treaty of Arbitration between Guatemala and Honduras (League of Nations Treaty Series, Vol. 137, p. 259; United Nations Reports of International Arbitral Awards (RIAA), Vol. II, p. 1365)), which offer an acceptable basis for defining the characteristic features of a watercourse (channels, centre, flow, etc.).

As early as 1912, Captain Eason, of the Bechuanaland Police, after having visited the area, described the northern channel as being twice the width of the southern channel (see paragraph 53 below). The aerial photographs of the area concerned taken between 1925 and 1985 show a northern channel that is wider than the southern one. The satellite pictures taken in June 1975, then in March 1995 and June 1996 - i.e., in both the dry and rainy seasons - show the northern channel as being wider than the southern channel. The Court concludes that apart from the season of flooding that is indeed the situation.

34. The Parties both agree that the flow, i.e., the volume of water carried, plays an important role, and for Namibia even a decisive role, in determining the main channel - although they do not reach the same conclusion.

According to the data submitted by Botswana,

"the northern channel conveys about twice as much flow as the southern channel. The mean discharge at Site II in the northern channel is 78.865 m3/s compared to 41.823 m3/s at Site I in the southern channel... Notice that the ratio of roughly 1:2 between [p1067] the mean discharges of the southern and northern channels also applies to the median and maximum discharges."

Namibia criticizes this choice of gauging points, as well as the methods used, and disputes the accuracy of the figures provided by Botswana. For its part, it contends that

"the southern channel carries not only the major portion, but substantially all of the flow of the River in the vicinity of Kasikili Island, while the northern channel has almost no longitudinal flow and is little more than a relict channel of the Zambezi floodplain".

Namibia provides the following figures for the volume of flow during the period from 30 April to 2 May 1998:

"In the main channel to the south of the Island, the flow was 247 m3/s, i.e., almost 60% of the total. In the northern channel it was 188 m3/s."

35. The Court is not in a position to reconcile the figures submitted by the Parties, who take a totally different approach to the definition of the channels concerned. In Botswana's presentation, the two channels around Kasikili/Sedudu Island are those visible on the map (reproduced on page 25 of this Judgment). For its part, Namibia argues, placing particular reliance on certain maps and images, in support of the existence of a major channel of the Chobe, of which the southern channel - visible throughout the year except when the river is in flood - merely constitutes the thalweg (see the aerial photograph reproduced on page 26 of this Judgment). According to Namibia, "the left bank [of this large channel] is marked by the line of high ground crossing the Island in a west-east direction". This is the channel said to carry "the largest proportion of the annual flow of the river" and therefore to constitute the main channel of the Chobe in the sector of Kasikili/Sedudu Island. On a number of the photographs and maps submitted by Namibia (including the photograph reproduced on page 26 of this Judgment), the banks of this channel, described as the main channel, are shown by means of arrows or by a continuous line.

36. Botswana vigorously disputes the existence of this channel. It states the following:

"[Firstly], the surmised Namibian waterway across the Island occupies one sixth to one fifth of the northern channel. Secondly, it traverses the high elevations of the Island. Thirdly, the proposed line of its left bank, on examination of the aerial photographs and satellite images, is not a bank but a narrow sub-channel. Fourthly, that line is not tree-lined; and fifthly, the lower eastern areas of the Island, on the evidence, are the more probable path of overflow of Zambezi floods."

[p1068]

Map Showing the Two Channels around Kasikili/Sedudu Island According to Botswana

[p1069]

Photograph Showing the Two Channels around Kasikili/Sedudu Island According to Namibia

[p1070]

In short, Botswana states, there is

"no independent evidence to support the existence of a 'channel', let alone a 'main' one across the Island in the terms of Article III of the Anglo-German Agreement of 1890".

37. The Court is of the opinion that the determination of the main channel must be made according to the low water baseline and not the floodline (see in this regard the practice referred to in paragraph 33 above). The evidence shows that when the river is in flood, the Island is submerged by flood water and the entire region takes on the appearance of an enormous lake. Since the two channels are then no longer distinguishable, it is not possible to determine the main channel in relation to the other channel. As for the channel described by Namibia as the main channel, the Court finds that the largest part of its bed remains dry for the greater part of the year. High sand bars which are among the highest points of the Island (927 metres above sea-level) are found there, but it must also be noted that it was in this bed that cultivation took place, according to the evidence of a 1943 aerial photograph submitted by both Parties. It is difficult to accept that this bed, generally dry, and which would occupy the south-western part of the Island, can be the bed of the main channel. The Court therefore is not persuaded by Namibia's argument concerning the existence of this major "main" channel whose visible southern channel would merely constitute the thalweg.

38. Namibia emphasizes the importance of the Chobe Ridge in the area in question as a "stable and clearly visible escarpment some 50 metres high"; it uses this as an argument for determining the main channel, by maintaining that the right bank of the southern channel, which follows the Chobe Ridge, has certain characteristics ("a steep, well-defined bank with a strip of riverine vegetation along it") that make it readily identifiable. The Court would observe that, even if one part of the right bank of this channel is easily identifiable from a distance, other parts of this bank are not, and neither is the left bank. The Court is therefore unable to conclude that, in terms of visibility - or of general physical appearance - the southern channel is to be preferred to the northern channel.

39. The Court turns now to the criteria put forward by Botswana concerning "bed profile configuration". The Court finds that the northern channel of the Chobe, around Kasikili/Sedudu Island, does not contain any of the meanders that are so typical of the secondary branches of watercourses. The southern channel, however, does show such meanders. Namibia indeed acknowledges the curved nature of the southern channel but, in light of the sediment deposition, draws contrary conclusions with regard to the importance of this channel. Having examined the arguments, maps and photographs put forward by the Parties, the Court is unable to conclude that, from its bed configuration, the southern channel constitutes the principal and natural prolongation of the course of the Chobe before the bifurcation. [p1071]

40. The navigability of a watercourse is the combined result of its depth, its width and the volume of water it carries, taking account of natural obstacles such as waterfalls, rapids, shallow points, etc., along its course. The Parties to the dispute do not accord equal importance to navigability in the determination of the main channel of the Chobe. Botswana maintains that "in the period at which the [1890] Treaty was concluded . . . navigability and access to navigable waters were primary considerations in the minds of the negotiators". In Namibia's view, on the other hand, "it would be anomalous to apply a criterion of navigability to a river boundary that is non-navigable for most of its length"; Namibia attaches no less importance to the actual use of the southern channel of the Chobe around Kasikili/Sedudu Island for the purpose of navigation by tourist vessels.

The Court notes that the navigability of watercourses varies greatly, depending on prevailing natural conditions. Those conditions can prevent the use of the watercourse in question by large vessels carrying substantial cargoes, but permit light flat-bottomed vessels to navigate. In the present case, the data furnished by the Parties tend to prove that the navigability of the two channels around Kasikili/Sedudu Island is limited by their shallowness. This situation inclines the Court to the view that, in this respect, the "main channel" in this part of the Chobe is that of the two which offers more favourable conditions for navigation. In the Court's view, it is the northern channel which meets this criterion.

In 1947, Mr. W. Ker, the proprietor of the Zambezi Transport & Trading Company, sought permission to transport timber by barge via the northern channel of the Chobe from Serondella (upstream) to Katambora (downstream), the southern channel being unusable for that purpose (see paragraph 56 below). The Court has no information regarding the volume of timber carried, the duration of this undertaking or its success; nor has it been informed of other attempts which may have been made to utilize the Chobe for navigational purposes. This absence of data enables the Court to conclude that the economic importance of navigation, even in the northern channel, has remained slight. However, it follows from the Trollope-Redman correspondence of 1948 - which correspondence the Court will consider later (see paragraph 58 below) - that the northern channel of the Chobe was regarded as a "stretch of water . . . navigable and giv[ing] access to the higher reaches of the Chobe - [unlike] the southern channel". This correspondence also indicates that "the Southern Channel [was] not navigable by [timber] barges when the river [was] not in flood".

Moreover, the use of the southern channel by flat-bottomed tourist boats does not in itself prove that the latter offers more favourable conditions for navigation than the northern channel. In the view of the Court, the presence of these tourist boats in the southern channel is attributable to the spectacle of large wild animals and the wealth of fauna [p1072] on the banks of the southern channel. The economic importance of tourism in the southern channel does not alter its conditions of navigability. The Court cannot therefore regard the amount of tourist craft in the southern channel as a reason for modifying the conclusion that it has reached above.

41. For the foregoing reasons, the Court concludes that, in accordance with the ordinary meaning of the terms that appear in the pertinent provision of the 1890 Treaty, the northern channel of the River Chobe around Kasikili/Sedudu Island must be regarded as its main channel.

42. This conclusion is supported by the results of various on-site investigations, as recorded in the reports drawn up on those occasions. The Court will revert in greater detail to these reports when it considers their legal significance in the course of its examination of the conduct of the Parties subsequent to the 1890 Treaty (see paragraphs 52-70 below). At this stage it would nonetheless note the following points:

(1) in 1912, Captain H. E. Eason, of the Bechuanaland Police, travelled through the area in question and concluded as follows in his reconnaissance report:

"Here [i.e., around Kissikiri (Kasikili) Island], I consider that undoubtedly the north should be claimed as the main channel. At the western end of the island the north channel at this period of the year is over one hundred feet wide and 8 feet deep, the south channel about forty feet wide and four feet deep. The south channel is merely a back water, what current there is goes round the North"

(2) a joint report drawn up on 19 January 1948 by Messrs. L. F. W. Trollope and N. V. Redman, respectively Magistrate of the Eastern Caprivi Strip and District Commissioner at Kasane (Bechuanaland), contains the following conclusions on this point:

"We express the opinion that the 'main Channel' lies in the waterway which would include the island in question in the Bechuanaland Protectorate";

(3) the joint report drawn up on 15 July 1985 by a joint team of experts from South Africa and Botswana resulted in the following conclusion: "The main channel of the Chobe River now passes Sidudu/Kasikili Island to the west and to the north of it."

Thus, the three on-site surveys carried out at different times concluded that the main channel of the River Chobe was the northern channel.

*

43. The Court will now consider how and to what extent the object and purpose of the treaty can clarify the meaning to be given to its terms. [p1073] While the treaty in question is not a boundary treaty proper but a treaty delimiting spheres of influence, the Parties nonetheless accept it as the treaty determining the boundary between their territories. The major concern of each contracting party was to protect its sphere of influence against any intervention by the other party and to obviate any risk of future disputes. Article VII of the 1890 Treaty is worded as follows:

"The two Powers engage that neither will interfere with any sphere of influence assigned to the other by Articles I to IV. One Power will not in the sphere of the other make acquisitions, conclude Treaties, accept sovereign rights or Protectorates, nor hinder the extension of influence of the other.

It is understood that no Companies nor individuals subject to one Power can exercise sovereign rights in a sphere assigned to the other, except with the assent of the latter."

The contracting powers, by opting for the words "centre of the main channel", intended to establish a boundary separating their spheres of influence even in the case of a river having more than one channel. They possessed only rudimentary information about the Chobe's channels. If they knew that such channels existed, their number, features, navigability, etc., and their relative importance remained unknown to them. This situation explains the method adopted to define the southern boundary of the Caprivi Strip.

The Court stated in the Temple of Preah Vihear, (Merits) case:

"There are boundary treaties which do no more than refer to a watershed line, or to a crest line, and which make no provision for any delimitation in addition." (I.C.J. Reports 1962, p. 34.)

In that Judgment the Court added that this was "an obvious and convenient way of describing a frontier line objectively, though in general terms" (ibid., p. 35). In the present case, the contracting parties employed a similar approach.

44. The Court notes that navigation appears to have been a factor in the choice of the contracting powers in delimiting their spheres of influence. The great rivers of Africa traditionally offered the colonial powers a highway penetrating deep into the African continent. It was to gain access to the Zambezi that Germany sought "a strip of territory which shall at no point be less than 20 English miles in width" - terms which were eventually included in the provisions of Article III, paragraph 2, of the Treaty. Admittedly, this strip of territory did provide access to the Zambezi, but its southern boundary was formed by the Chobe River, which was apparently assumed to be navigable, as suggested by the use of [p1074] the word "thalweg" in the text of the German version of the Treaty. The difficulties of the land route owing to regular flooding, and the obstacles to navigation on the Chobe, were, in all probability, little known at the time.

45. The fact that the words "centre of the main channel" were included in the draft Treaty on the initiative of the British Government suggests that Great Britain no less than Germany sought to have access to the Zambezi. In order to mark the separation of their spheres of influence, the contracting parties chose "the centre of the main channel" of the Chobe, thus ensuring that there was a well-defined, recognizable boundary, in a watercourse that was assumed to be navigable. There are grounds for thinking that one of the reasons underlying their decision was navigation, but the Court does not consider that navigation was the sole objective of the provisions of Article III, paragraph 2, of the Treaty. In referring to the main channel of the Chobe, the parties sought both to secure for themselves freedom of navigation on the river and to delimit as precisely as possible their respective spheres of influence.

**

46. The travaux preparatoires of the Treaty concerning south-west Africa and the Caprivi Strip in particular support this reasoning.

Initial attempts to record the parties' agreement described the boundary simply as following the course of the Chobe, without reference to any channel. Article II of the provisional agreement initialled by Lord Salisbury and Count Hatzfeldt on 17 June 1890 stipulated:

"The frontier between the German territory and the English territory in the south-west of Africa shall follow, from the point which has been agreed upon in previous arrangements, the 22nd degree of south latitude (leaving Lake Ngami to England), to the east up to the 21st degree of longitude; from thence to the north to where that degree touches the 18th degree of south latitude. Thence, the line of demarcation shall be carried to the east along the centre of the River Tschobi, up to the point where it flows into the Zambesi."
The text subsequently prepared by the British and German negotiators, and transmitted to the British Foreign Office on 21 June 1890, as "a draft of the Articles of Agreement" was worded:

"[The boundary] runs eastward along that parallel till it reaches the River Chobe, and descends the centre of that river to its junction with the Zambesi, where it terminates. It is understood that, under this arrangement, Germany shall have free access from her Protectorate to the Zambesi by the Chobe."

On 25 June 1890, the British side proposed the following wording: "In [p1075] paragraph 2 of Article III, after the words 'the River Chobe, and descends the centre of,' the words 'the main channel of' should be inserted."

The proposal was accepted by the German side and translated as "in der Thal-Linie des Hauptlaufes dieses Flusses". In the end the word Thal-Linie was replaced by the word Thalweg. The German text is therefore a word-for-word translation of the British proposal and follows the English text. Therefore, it may reasonably be supposed that these terms are synonymous and that the English text, like the German text, correctly and accurately expresses the will of the contracting parties.

**

47. In the course of the proceedings, Botswana and Namibia made abundant reference to the subsequent practice of the parties to the 1890 Treaty - and of their successors - as an element in the interpretation of that Treaty.

48. Article 31, paragraph 3, of the 1969 Vienna Convention on the Law of Treaties, which, as stated earlier, reflects customary law (see paragraph 18 above), provides as follows:

"Article 31

General rule of interpretation
……………………………………………………………………………………………
3. There shall be taken into account, together with the context:

(a) any subsequent agreement between the parties regarding the interpretation of the treaty or the application of its provisions;

(b) any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation;
…………………………………………………………………………………………..”

49. In relation to "subsequent agreement" as referred to in subparagraph (a) of this provision, the International Law Commission, in its commentary on what was then Article 27 of the draft Convention, stated the following:


"an agreement as to the interpretation of a provision reached after the conclusion of the treaty represents an authentic interpretation by the parties which must be read into the treaty for purposes of its interpretation" (Yearbook of the International Law Commission, 1966, Vol. II, p. 221, para. 14).

As regards the "subsequent practice" referred to in subparagraph (b) of the above provision, the Commission, in that same commentary, indicated its particular importance in the following terms:

"The importance of such subsequent practice in the application of the treaty, as an element of interpretation, is obvious; for it constitutes objective evidence of the understanding of the parties as to the [p1076] meaning of the treaty. Recourse to it as a means of interpretation is well-established in the jurisprudence of international tribunals." (Ibid., p. 241, para. 15.)

50. Indeed in the past, when called upon to interpret the provisions of a treaty, the Court has itself frequently examined the subsequent practice of the parties in the application of that treaty (see for example, Corfu Channel, Merits, Judgment, I.C.J. Reports 1949, p. 25; Arbitral Award Made by the King of Spain on 23 December 1906, Judgment, I.C.J. Reports 1960, pp. 206-207; Temple of Preah Vihear, Merits, Judgment, I.C.J. Reports 1962, pp. 33-35; Certain Expenses of the United Nations (Article 17, paragraph 2, of the Charter), Advisory Opinion, I.C.J. Reports 1962, pp. 157, 160-161 and 172-175; Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Jurisdiction and Admissibility, Judgment, I.C.J. Reports 1984, pp. 408-413, paras. 36-47; Territorial Dispute (Libyan Arab Jamahiriya/Chad), Judgment, I.C.J. Reports 1994, pp. 34-37, paras. 66-71; Legality of the Use by a State of Nuclear Weapons in Armed Conflict, Advisory Opinion, I.C.J. Reports 1996, (l), p. 75, para. 19).

51. While the Parties to the present proceedings both accept that interpretative agreements and subsequent practice do constitute elements of treaty interpretation under international law, they disagree on the consequences to be drawn from the facts in this case for purposes of the interpretation of the 1890 Treaty.

*

52. In support of its interpretation of Article III, paragraph 2, of the 1890 Treaty, Botswana relies principally on three sets of documents: a report on a reconnaissance of the Chobe produced in August 1912 by an officer of the Bechuanaland Protectorate Police, Captain Eason; an arrangement arrived at in August 1951 between Major Trollope, Magistrate for the Eastern Caprivi, and Mr. Dickinson, a District Commissioner in the Bechuanaland Protectorate, together with the correspondence that preceded and followed that arrangement; and an agreement concluded in December 1984 between the authorities of Botswana and South Africa for the conduct of a Joint Survey of the Chobe, together with the resultant Survey Report.

The Court will examine each of these three sets of documents in turn, in order to determine what conclusions may be drawn from them in the light of the rules set out in Article 31, paragraph 3, of the Vienna Convention.

53. About the year 1910, negotiations took place between Germany and Great Britain concerning the boundary between their respective possessions in the area of the Caprivi Strip west of the intersection of the 18th parallel with the River Chobe, and arbitration of the matter was considered. [p1077]

Anticipating a possible extension of the discussions to include the boundary east of that point, the British Secretary of State for the Colonies, in a letter dated 14 July 1911 to the High Commissioner responsible for Bechuanaland, expressed himself in the following terms:

"I take this opportunity of observing that in the second clause of Article III of the Anglo-German Agreement of 1890 it is stated that the boundary 'descends the centre of the main channel of that river (i.e., the River Chobe) to its junction with the Zambesi.' As, in this section of its course, the River Chobe divides into more than one channel which afterwards reunite, the question as to which is the main channel will require consideration.

I have to request . . . that I may receive all available information from local sources in support of the view that the north channel is the main channel. Such information should be accompanied by a map and, if possible, by measurements of the streams, and should be in a form which can, if necessary, be laid before the arbitrator as part of the case of His Majesty's Government."

This was the context in which Captain Eason was instructed to prepare a "Report on the main channel of the Linyanti (or Chobe) river". That Report, which bears the date 5 August 1912, contains, inter alia, the following passage:

"Two miles above the rapids lies Kissikiri Island. Here I consider that undoubtedly the North should be claimed as the main channel. At the Western end of the island the North channel at this period of the year is over one hundred feet wide and eight feet deep, the South channel about forty feet wide and four feet deep. The South channel is merely a back water, what current there is goes round the North. The natives living at Kasika in German territory are at present growing crops on it."

It is not disputed that Kissikiri Island is the island later known as Kasikili/Sedudu.

54. In its Memorial, Botswana claimed that the Eason Report represented practice in the application of the 1890 Treaty. Namibia disputed this, pointing out inter alia that Great Britain had not made any claim on this basis, even though its exchanges with Germany concerning the rest of the southern boundary continued until the outbreak of the First World War. However, in the final version of its argument, Botswana, while continuing to rely on the Eason Report for other purposes, accepted that it could not be regarded as evidence of subsequent practice relating to the application of the 1890 Treaty.

55. The Court shares the view that the Eason Report and its surround-[p1078]ing circumstances cannot be regarded as representing "subsequent practice in the application of the treaty" of 1890, within the meaning of Article 31, paragraph 3 (b), of the Vienna Convention. It notes that the Report appears never to have been made known to Germany and to have remained at all times an internal document. The Court observes, moreover, that the British Government itself never took the Report any further, whether immediately afterwards (the anticipated arbitration not having taken place) or later on (for example when the Caprivi Strip was occupied by British troops during the First World War, or when it was administered by the British authorities on behalf of South Africa between 1921 and 1929).

56. In 1947, Mr. Ker, who was operating a transport business in Bechuanaland, planned to bring timber down the Chobe using the northern channel. He obtained the necessary permission from the competent official in the Caprivi Strip, Major Trollope, but also raised the matter with the Bechuanaland authorities. Correspondence then ensued between Major Trollope and the Assistant District Commissioner at Maun (Bechuanaland), Mr. Redman. In a letter dated 18 December 1947, Mr. Redman wrote to Major Trollope as follows:

"1. I have the honour to inform you that I have received a letter from the Zambesi Transport & Trading Company stating that they wish to recommence the transport of timber by river from Serondella but they have been informed by you that the channel between Kasane and Serondella which they intend to use, is in the Caprivi Strip.

2. At low water I understand that this channel is the only water connection between Kasane and Serondella and I suggest that if this channel does happen to run into the Caprivi Strip from the Chobe river along which our boundary runs it will be in both our interests and a matter of convenience if we can come to an arbitrary agreement that half this channel is included in this Territory for the purpose of the transport of the timber by the Zambesi Transport & Trading Company.

3. If however the channel referred to is part of the Chobe river and not a branch off from it then it seems probable that the actual boundary is formed by the deep water channel in the river, which would mean that they would not be entering your Territory.

4. I would be glad to have your views on this matter."

In his reply of 3 January 1948 Major Trollope informed Mr. Redman that he was prepared to renew indefinitely the permission originally given to Mr. Ker for a period of six months; and he added:

"4. In regard to the larger question raised by you (i.e. as to whether the stretch of water in question is actually within the East-[p1079]ern Caprivi Zipfel, - or whether it in fact forms the boundary), I freely admit that the matter is not without difficulty. I further agree that it is a matter affecting our two administrations and is not merely a matter between this office and Mr. Ker.

5. I suggest, in this connection, that I and your Assistant at Kasane, should hold a joint informal investigation thereafter submitting reports (joint if we are able to reach unanimity) to our respective administrations in order to resolve the matter finally and officially."


57. On 19 January 1948, Major Trollope and Mr. Redman (at the time District Commissioner at Kasane, Bechuanaland) produced a Joint Report entitled "Boundary between the Bechuanaland Protectorate and the Eastern Caprivi Zipfel: Kasikili Island", in which, after citing the provisions of Article III, paragraph 2, of the 1890 Treaty, they stated the following:

"3. We find after separate examination of the terrain and the examination of an aerial photograph that the 'main Channel' does not follow the waterway which is usually shown on maps as the boundary between the two Territories.

4. We express the opinion that the 'main Channel' lies in the waterway which would include the island in question in the Bechuanaland Protectorate.

5. On the other hand we are satisfied, after enquiry that since at least 1907, use has been made of the Island by Eastern Caprivi Zipfel tribesmen and that that position still continues.

6. We know of no evidence of the Island having been made use of, or claimed, by Bechuanaland Tribesmen or Authorities or of any objection to the use thereof by Caprivi Tribesmen being made.

7. We record, however, the fact that the country on the Bechuanaland side of the boundary is for all practical purposes not tribally occupied by Africans.

8. We record the foregoing as facts particularly recording that we have neither arrived at, nor expressed any joint opinion on the effect of these facts on the ownership of the Island."

58. Major Trollope sent a copy of the Report to the Secretary of Native Affairs at Pretoria under cover of a letter of 21 January 1948, in which he stated inter alia the following:

"The terms of the Treaty are very definitive and, as I have already pointed out, favour the Bechuanaland contention. It is not without point, however, that we are - by occupation - in the position of the possessor and the onus would appear to lie on the Protectorate to prove their case in order to disturb our possession." [p1080]

He proposed various solutions, after first pointing out that "the Bechuanaland authorities are anxious to have the northern channel recognised as the boundary because that stretch of water is navigable and gives access to the higher reaches of the Chobe - which is not the case in respect of the southern channel".

For his part, Mr. Redman forwarded a copy of the Joint Report to the Government Secretary at Mafeking, under cover of a letter of 26 January 1948, in which he stated inter alia that: "the Southern Channel [was] not navigable by [Mr. Ker's] Barges when the river [was] not in flood" and that it was "even difficult for small craft to navigate it"; that "the map, which show[ed] the boundary to follow the Southern Channel, [was] . . . inaccurate and [had] probably [been] drawn by some-one who had not examined the river to determine the main Channel"; that according to "further information from an inhabitant of the Island . . . in 1924 a Caprivi Chief . . . [had] applied to . . . the Resident Magistrate at Kasane, for permission for his people to plough on the Island"; and that "surrender of this Island would prevent this Territory from having free use of the Chobe River, which [might] one day become an extremely important waterway".

59. After Major Trollope and Mr. Redman forwarded the Joint Report of 19 January 1948 to their respective authorities, there ensued an extended correspondence between those authorities.

On 14 October 1948 the Secretary to the South African Prime Minister with responsibility for External Affairs wrote to the Administrative Secretary to the High Commissioner for Bechuanaland in Pretoria, stating that, while he noted the findings of the Trollope-Redman Report with regard to the identification of the "main channel" around Kasikili Island, he wished to propose an arrangement in the following terms:

"The Union Government is anxious to preserve the rights of the Caprivi Zipfel tribesmen on the Island and it is understood that the Bechuanaland authorities desire the use of the Northern channel for navigation purposes. As there would appear to be no conflict of interests it should be possible to come to an arrangement which is mutually satisfactory. Your views in the matter would be appreciated."

The Administrative Secretary replied on 4 November 1948 that

"the Resident Commissioner of the Bechuanaland Protectorate has directed the Assistant District Commissioner, Kasane, that tribesmen of the Caprivi Zipfel should be allowed to cultivate land on Kasikili Island, if they wish to do so, under an annual renewable permit".

This reply did not appear to satisfy the Secretary for External Affairs of South Africa, who wrote back to the Administrative Secretary on 14 February 1949 in the following terms:

"While noting that your Administration is prepared to authorise [p1081] Caprivi Zipfel tribesmen to cultivate land on Kasikile Island on an annual renewable permit, I am to state that this is not what the Union Government had in mind.

From the available information it is clear that Caprivi Tribesmen have made use of the Island for a considerable number of years and that their right to do so has at no time been disputed either by Bechuanaland Tribesmen or the Bechuanaland authorities.

It was further understood that the interests of the Bechuanaland authorities centred in the use of the Northern Channel of the Chobe for navigation purposes.

My object in writing to you was therefore to ascertain whether agreement could not be reached on the basis of your Administration recognising the Union's claim to Kasikile Island subject to it issuing a general permit for the use of the Northern waterway for navigation purposes."

On 6 June 1949 the High Commissioner for Bechuanaland wrote to the Secretary of State for Commonwealth Relations in London informing him of the South African proposal. In his letter the High Commissioner stated that the Union Government had "proposed a slight adjustment of the northern boundary of the Bechuanaland Protectorate"; he explained that Kasikili Island had "hitherto been regarded as part of the Caprivi Zipfel, since maps show[ed] that the main channel pass[ed] to the south of the island"; with reference to the Joint Report of 19 January 1948, which he enclosed with his letter, he stated that

"the question of the correct boundary was raised by a firm which intends to transport timber down the river, and the Union Government, having examined the question, find that the main channel is to the north of the island, and that there has been no change in the course of the channel within living memory";

and he concluded:

"4. The Resident Commissioner of the Bechuanaland Protectorate considers that the Union proposal to set the boundary in the southern channel need not be resisted, if the use of the northern channel for navigation is guaranteed for the inhabitants and Government of the Bechuanaland Protectorate. This guarantee the Union Government are prepared to give.

5. I consider in the circumstances that the proposal of the Union Government is acceptable, and would be glad to have your approval of it."

Ultimately, following consultations with the Commonwealth Relations Office, Bechuanaland declined to accept the South African proposal. This reaction appears to have been motivated, in particular, by difficulties in [p1082] connection with the Mandate over South West Africa. Thus, in a letter dated 24 August 1949, the Chief Secretary to the High Commissioner for Bechuanaland explained to the Secretary to the South African Prime Minister, that "while the slight alteration proposed [by the South African Government] seem[ed] of little intrinsic importance, an examination of the legal and political aspects ha[d] revealed that certain difficulties [might] ensue both from the standpoint of international law and as regards possible uncertainty of jurisdiction". These points were explained as follows in a long letter dated 20 October 1949 from the Commonwealth Relations Office in London to the High Commissioner for Bechuanaland:

"we agree that this very slight alteration is of no intrinsic importance in itself and seems in substance unobjectionable. There are, however, certain legal and political complications which it seems necessary to bring to your notice . . . First, there is the international aspect . . . Under Article 7 of the Mandate no modification could be made without the consent of the Council of the League of Nations. In so far as the mandate is still operative, this might be interpreted as referring to some organ of the United Nations or as making any adjustment impossible. No doubt it is unlikely that anyone would raise any objection in the United Nations, especially as the proposal is to add to the territory and not in any way to reduce its area, but the possibility cannot be entirely ignored. Secondly, it is necessary to consider the effect of the adjustment from the point of view of Municipal Law. This is more difficult. The island is apparently inhabited and no doubt offences are sometimes committed and civil disputes might occur. . . . The matter being thus dependent on an agreement between the United Kingdom and Germany, at first sight there is no reason why an adjustment, fully effective for the purposes of Municipal Law, should not be made by a further agreement between the United Kingdom and the Union of South Africa. Unfortunately, however, the International Law on the subject affects the Municipal Law, for the mandate creates a technical difficulty . . . The issue of an Order in Council involving a cession of territory, however small or nominal, to South West Africa is open to some objection since the publicity involved might arouse curiosity and subsequent criticism on the part of those who dislike the Union Government's refusal to place South West Africa under trusteeship."

On 10 May 1951 the High Commissioner wrote in similar terms to the Secretary to the South African Prime Minister, stating that: [p1083]

"The possibility of making a declaration on behalf of the Government of the Bechuanaland Protectorate to the effect that the Island is not claimed as lying within the boundaries of the Protectorate has been examined by the Legal Advisers to the Secretary of State for Commonwealth Relations. I am afraid that they have found this proposal to be beset by legal complications of an international nature, the solution of which would entail difficulties disproportionate to the importance of the matter at issue";

and adding:

"The Bechuanaland Protectorate Government might possibly wish to arrange for some land on the Island at some time to be cultivated by the few African public servants at Kasane. Apart from this minor matter, I venture to suggest that it is unlikely that any development in the foreseeable future will damage the interests of the Caprivi tribesmen who have in the past used the Island. It should, I think, be possible to adjust by administrative action any difficulty arising in connection with the Island and the adjacent waterway without an alteration of the existing legal position . . . and it is assumed that the free use of the main channel of the Chobe, to the north of the Island, would continue to be assured under the international rules governing waterways that form the common boundary of two states."

60. It was in very similar terms that Mr. Dickinson, who had in the meantime succeeded Mr. Redman as District Commissioner at Kasane (Bechuanaland) wrote on 5 July 1951 to Major Trollope "in regard to Kasikili Island". After explaining that "the legal complications which are of an international nature, and beset the question of excorporating Kasikili Island from the Bechuanaland
Protectorate, will involve difficulties disproportionate to the matter at issue", he concluded as follows:

"Might I therefore say that the position as at the moment, allowing the full use of the Island to your tribesmen, for grazing and cultivation and our undisputed use of the Northern Waterway, under the international laws, governing the Waterways forming the common boundaries of two states, would appear entirely satisfactory, to the B.P. Government, and I trust also to yours."

In his reply of 4 August 1951 Major Trollope agreed that "the 'stink' [was] quite disproportionate to the importance of the matter at issue", adding that they should "let the whole matter lapse into the decent obscurity from which it should never have been allowed to emerge". However, he disagreed with certain of the language used in Mr. Dickinson's letter, observing: [p1084]

"I find it, however, somewhat embarrassing to agree formally that we should be 'allowed' the use of the Island and should recognise the 'undisputed use of the Northern Waterway under the international laws governing the waterways forming the common boundary of two states'. Such an agreement might quite possibly be arguably used in support of a submission that we occupy by licence and permission - which we do not, of course, admit."

Major Trollope accordingly proposed the following "gentlemen's agreement":

"(a) That we agree to differ on the legal aspect regarding Kasikili Island, and the concomitant question of the Northern Waterway;

(b) That the administrative arrangements which we hereafter make are entirely without prejudice to the rights of the Protectorate and the Strip to pursue the legal question mentioned in (a) should it at any time seem desirable to do so and will not be used as an argument that either territory has made any admissions or abandoned any claims; and

(c) That, having regard to the foregoing, the position revert to what it was de facto before the whole question was made an issue in 1947 - i.e. that Kasikili Island continue to be used by Caprivi tribesmen and that the Northern Waterway continue to be used as a 'free for all' thoroughfare."

Major Trollope made it clear that:

"this 'gentlemen's agreement' could only purport to affect arrangements as between our two Administrations. I have my gravest doubts as to the wisdom of making the ambit larger for that would bring in all sorts of extraneous questions of international law and such like imponderables which I think we might usefully leave for consideration when we come to that bridge."

In a letter of 11 August 1951 Mr. Dickinson stated that the three-point agreement proposed by Major Trollope seemed to him "the most reasonable solution" and that he "agree[d] entirely with [it]". He suggested, however, that a paragraph (d) be added, stating "that nothing in the previous three sections should be read as preventing the [Bechuanaland Protectorate] Tribesmen using the Island for ploughing purposes".

On 23 August 1951 Major Trollope replied as follows:

"1. I'm afraid that the point you raise rather throws a spanner in the works.

2. I appreciated the position as that we both wished to restore the factual position to what it was before Ker raised the hornet's nest, and to leave the legal position 'in the air' to be freely raised in the future by either side should that become necessary or desirable.

3. Whatever the legal position (i.e. whether your tribesmen have any rights) is, the [p1085] factual position is that not in all the years past - not in German times, nor when the Strip was administered by the B.P., nor in the S.W. African days nor during my administration (Union) - have B.P. tribesmen ever cultivated the Island or asserted a right to do so; while Caprivi tribesmen have always done so (see paras. five and six of the Joint Report of 19/1/1948 by Redman and myself). For me to agree therefore that there is nothing to prevent B.P. tribesmen from cultivating the Island does not seem to me to restore the Status quo . . ."

To this, Mr. Dickinson responded on 3 September 1951 as follows:

"I must concede your point rather than allow the 'spanner' to 'bust' the works.

Your paragraphs (a), (b), & (c) will then meet the points in question. In other words we revert to the position as it was prior to this disturbance.

I feel I must make one point clear to you. Although accepting the position and being prepared to honour it, in any discussion or controversy on this Island in future, our Government will be adamant in its attitude that the Island is B.P. - and any attitude in regard to our 'Administrative Settlements' will of course be based on that fact."

Finally, on 13 September 1951, Major Trollope wrote as follows to the new District Commissioner at Kasane, Mr. McLaren:

"2. I really feel that the possibility of future 'discussion or controversy' regarding Kasikili is extremely remote. After all the present factual position, to which happily we now return, has existed for generations without any conflict - indeed, in my opinion, even the recent contretemps was unnecessary.

3. However, if circumstances again make it necessary for controversy to rear its head, the fact of Dickinson's caveat is now on record. Perhaps it would not be inappropriate were I likewise formally to record that in any future controversy over this Island, the Caprivi will be equally insistent on asserting the legality of the factual possession and use it has enjoyed for so many years.
------------------------------------------------------------------------------------------------------------[p1086]

5. I propose now, if you agree, advising my Department that there is no necessity for pursuit of the matter at high levels as a suitable administrative arrangement, without any prejudice whatever to either side, has been concluded between my office and yours . . .

P.S. It occurs to me that the most likely way in which, unwittingly and not designedly, the controversy might be re-opened is by a B.P. tribesman 'trespassing' (as it would be regarded by us, although not legally by you) on Kasikili. I hereby undertake that should any such occasion arise I will not deal with the matter without prior reference to your office to ascertain whether you wish the large question raised. May I tentatively suggest that you advise your tribesmen to avoid any such action - unless, of course, it is deliberately done as an assertion of right to test the position."

This resulted in the despatch of a letter dated 20 November 1951 from the Government Secretary at Mafeking to the District Commissioner at Kasane, which included the following passage:

"The Native Commissioner Eastern Caprivi Zipfel may therefore be informed that his recommendation is accepted.

2. It is understood that the only Africans in the Protectorate interested in the cultivation of the Island are Government employees living at Kasane and I am to say that they should be instructed that they will not be permitted to plough on the Island."

61. Each of the Parties to the present proceedings relies on the Trollope-Redman Joint Report and the correspondence relating thereto in support of its position. The consequences that they draw from them, however, differ significantly. According to Botswana, these documents show that the boundary around Kasikili/Sedudu Island follows the northern channel; Namibia disputes this, claiming that those same documents demonstrate that the Island forms part of the Caprivi Strip.

62. From the various administrative and diplomatic documents referred to above, the Court, for its part, observes the following: (1) prior to 1947 no differences had arisen between Bechuanaland and the power administering the Caprivi Strip with regard to the boundary in the area of Kasikili/Sedudu Island; (2) it appears that, on the basis of the maps available at the time, the boundary had until then been supposed to be located in the southern channel of the Chobe; (3) in 1948 a local official from the Caprivi and a local official from Bechuanaland came to the joint conclusion, "after separate examination of the terrain and the examination of an aerial photograph", that the "main channel" around Kasikili/Sedudu Island was the northern one (without specifying what criteria they had employed); at the same time they noted that since at least 1907 [p1087] use had been made of the Island by Caprivi tribesmen without objection by the Bechuanaland authorities and that that situation still continued; and they recorded that they had "neither arrived at, nor expressed any joint opinion on the effect of these facts on the ownership of the Island"; (4) the higher authorities in Bechuanaland subsequently took the view that the boundary around the Island was located in the northern channel of the Chobe, and that South Africa's claims to the Island itself were unfounded under the 1890 Treaty; nevertheless, they were initially inclined to accept those claims, on condition that they retained access to the northern channel, but later, after consulting London, they abandoned that idea, fearing that this would result in a modification of the boundary that, in view of the mandate over South West Africa, would give rise to a variety of complications; (5) the higher authorities in South Africa, while not disputing the possibility of the "main channel" around Kasikili/Sedudu Island being the northern one and at the same time demonstrating a flexible attitude with regard to access to that channel, clearly asserted their claims to the Island; (6) the local officials in the Caprivi Strip and in Bechuanaland, aware of the positions of their respective superior authorities but keen to remain on neighbourly terms, agreed to shelve their legal differences and to maintain, until further notice, the status quo ante (use of Kasikili/Sedudu Island by Caprivi tribesmen and open access to the northern channel of the Chobe); (7) the local official in the Caprivi Strip described the question of the "Northern Waterway" as "concomitant" with that of the "legal aspect regarding Kasikili Island", and his counterpart in Bechuanaland did not challenge this; (8) the issue of access to the Island by Bechuanaland tribesmen was not pursued further.

63. From all of the foregoing, the Court concludes that the above-mentioned events, which occurred between 1947 and 1951, demonstrate the absence of agreement between South Africa and Bechuanaland with regard to the location of the boundary around Kasikili/Sedudu Island and the status of the Island. Those events cannot therefore constitute "subsequent practice in the application of the treaty [of 1890] which establishes the agreement of the parties regarding its interpretation" (1969 Vienna Convention on the Law of Treaties, Art. 31, para. 3 (b)). A fortiori, they cannot have given rise to an "agreement between the parties regarding the interpretation of the treaty or the application of its provisions" (ibid., Art. 31, para. 3 (a)).

64. In October 1984 an incident during which shots were fired took place between members of the Botswana Defence Force and South African soldiers who were travelling by boat in the Chobe's southern channel. At a meeting held in Pretoria on 19 December 1984 between representatives of various South African and Botswanan ministries, it emerged that the incident had arisen out of differences of interpretation as to the precise location of the boundary around Kasikili/Sedudu Island. At this meeting, reference was made to the terms of the 1890 Treaty and it was [p1088] agreed "that a joint survey should take place as a matter of urgency to determine whether the main Channel of the Chobe River is located to the north or the south of the Sidudu/Kasikili Island".

The joint survey was carried out at the beginning of July 1985. The "survey report", drawn up on 15 July 1985, was preceded by an analysis of the available maps stating that, while those prior to 1975 located the boundary in the southern channel, Botswana had in 1975 published a map which placed the boundary to the north and west of the Island: it was concluded from this that "[t]he disparity in the depiction of the boundary between South African maps and those ofBotswana had probably been a contributory factor in the recent border incident near Kasane". Furthermore, the report was also preceded by a paragraph entitled "Authority for Survey", which stated:

"At an intergovernmental meeting held in Pretoria on 19 December 1984 it was decided that a joint survey should be undertaken to determine whether the main channel of the Chobe River is located to the north or the south of Sidudu/Kasikili Island.

Representatives of the two national survey organisations accompanied by co-workers from the Departments of Water Affairs have now been to the area to survey the 'Thalweg' in the vicinity of the island. Specific mention is made to the Thalweg in the 1890 Agreement between England and Germany."

The report itself gave details of the cross-sections and depth soundings taken and the equipment used; it contained inter alia the following passage:

"Livestock from Caprivi are swum across the river when grazing on the Caprivi side is poor. The impression was gained that visits to the Island had, in recent years, become infrequent. Benson Mafwila [an elderly inhabitant of Kabuta village] recounted that Tax had been paid at Kasane in the Nineteen-twenties. He was referring, no doubt, to the period 1922-1929 when the Caprivi Strip was administered on behalf of South Africa by the Protectorate Government. The name by which the Island is known to Caprivians is Kasikili. This is also the Caprivian name for the arm of the river which flows around the island to the west and north. The name Sidudu Island is a later name coming from the Botswana side. There is a Sidudu valley in the immediate vicinity to the south."

The conclusions of the survey report were as follows:

"The main channel of the Chobe River now passes Sidudu/Kasikili Island to the west and to the north of it. (See annexed Map C.)

The evidence available seems to point to the fact that this has been the case, at least, since 1912. [p1089]

It was not possible to ascertain whether a particularly heavy flood changed the course of the river between 1890 and 1912. Capped Eason of the Bechuanaland Protectorate Police states, on page 4 of Part I of the report which has been referred to earlier, that floods occurred in 1899 and in June and July of 1909.

If the main channel of the river was ever situated to the south of the island, it is probable that erosion in the Sidudu Valley, the location of which can be seen in the annexed Map C, has caused the partial silting up of the southern channel.

Air photographs showing the channels of the river in the vicinity of the island are available in the archives of the two national survey organisations. They were taken in 1925, 1943, 1972, 1977, 1981 and 1982. No substantial change in the position of the channels is evident from the photographs."

65. The Department of External Affairs of Botswana officially forwarded a copy of this joint survey to South Africa's Department of Foreign Affairs under cover of a Note dated 4 November 1985 which included the following passage:

"The Department of Foreign Affairs will recall that one of the decisions taken at the meeting on 19 December was to send a joint team of technical experts to the Chobe to determine the boundary between Botswana and Namibia in the Sidudu/Kasikili Island area. The Department of External Affairs is pleased to attach to this Note copy of the report produced by the joint team of experts together with its annexes and would be grateful to know whether or not the South African sides wishes to have a meeting called to adopt the report formally. Alternatively the South African side could simply signify its acceptance of the conclusions of the report by means of a Diplomatic Note."

66. It would appear that South Africa never responded to this Note. On 13 October 1986 officials of the ministries of foreign affairs of Botswana and South Africa held a meeting at which the matter of Kasikili/Sedudu Island was briefly discussed. According to the record of this meeting drawn up by the Botswana side, the head of the South African delegation "suggested the maintenance of the status quo till political circumstances could permit direct negotiations between Botswana and independent Namibia"; the head of the Botswana delegation replied "that there was no more room for negotiations because a joint Botswana-South Africa team of experts had confirmed that the Island belonged to Botswana"; and the South African representative "decided to go back to look at this question once again".

On 22 October 1986 the Botswana authorities sent a telex to Pretoria in which they referred to the discussions of 13 October and went on to say: [p1090]

"It will be recalled that the Botswana side submitted that Sidudu/Kasikili Island is part of the territory of Botswana, as confirmed by the Botswana/South Africa Joint Team of Experts which reported to the two Governments in July, 1985. [We] wish to inform [you] that the Government of Botswana has since occupied Sidudu/Kasikili Island and expects the Government of South Africa to respect the sovereignty and territorial integrity of the Republic of Botswana in respect of the Island."

The South African authorities replied in the following terms:

"- The Sidudu/Kasikili border issue addresses the international boundary between Botswana and South West Africa/Namibia.

- According to International Law, such cases should be discussed between the two countries concerned. It is therefore suggested that the Cabinet of South West Africa/Namibia should be approached by the Botswana Government for a proper resolution of the matter under consideration.

- Alternatively, the South African Government would be willing to convene a meeting where Botswana, South West Africa/Namibia and South Africa could all be represented and where the relevant issue could be finalized."


The exchange ended with a telex from the Botswana authorities dated 25 November 1986, which read as follows:

"The joint Botswana/South Africa team of experts were never asked to demarcate an international boundary but 'to determine whether the main channel of the Chobe River is located to the north or south of Sidudu Island'. The Joint Team confirmed what had always been the fact, namely that the main channel is located to the north of the island, and that is where the boundary is.

It is therefore clear that adequate clarification of the matter has been made to satisfy normal requirements and no further discussion of the matter is necessary."

67. In these proceedings, Botswana contends that the decision taken in December 1984 to carry out a joint survey, and all the documents relating to that decision - including the survey of July 1985 itself - constitute an "intergovernmental agreement . . . between the parties regarding . . . the application" of the 1890 Treaty, which confirmed that the boundary around Kasikili/Sedudu Island was located in the northern channel of the Chobe. Botswana points out inter alia that "general international law do[es] not require any particular formality for the conclusion of an international agreement" and that "[t]he only criterion is the intention of the parties to conclude a binding agreement and this can be inferred from the circumstances". [p1091]

Namibia categorically denies that the discussions conducted between the Botswana and South African authorities in 1984-1985 led to an agreement on the boundary; it stresses in this connection that the July 1985 joint survey was not "self-executing" and was devoid of any legally binding status unless the parties concerned took the appropriate measures to confer such status upon it. Namibia points out that, once the United Nations General Assembly had terminated South Africa's mandate over South West Africa in 1966, neither South Africa nor Botswana could in any case conclude any kind of agreement on the boundaries of this territory.

68. Having examined the documents referred to above, the Court cannot conclude therefrom that in 1984-1985 South Africa and Botswana had agreed on anything more than the despatch of the joint team of experts. In particular, the Court cannot conclude that the two States agreed in some fashion or other to recognize themselves as legally bound by the results of the joint survey carried out in July 1985. Neither the record of the meeting held in Pretoria on 19 December 1984 nor the experts' terms of reference serve to establish that any such agreement was reached. Moreover, the subsequent correspondence between the South African and Botswana authorities appears to deny the existence of any such agreement: in its Note of 4 November 1985 (see paragraph 65 above), Botswana called upon South Africa to accept the survey conclusions; not only did South Africa fail to accept them but on several occasions it emphasized the need for Botswana to negotiate and agree on the question of the boundary with the relevant authorities of South West Africa/Namibia, or indeed of the future independent Namibia.

69. The Court has reached the conclusion that there was no agreement between South Africa and Botswana "regarding the . . . application of the [1890 Treaty]". This is in itself sufficient to dispose of the matter. It is unnecessary to add that in 1984 and 1985 the two States had no competence to conclude such an agreement, since at that time the United Nations General Assembly had already terminated South Africa's Mandate over South West Africa by resolution 2145 (XXI) of 27 October 1966, and the Security Council had approved that measure by resolution 276 (1970) of 30 January 1970. The Court itself, in its Advisory Opinion of 21 June 1971 on the Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970), stated the following in this regard:

"(1) . . . the continued presence of South Africa in Namibia being illegal, South Africa is under obligation to withdraw its administration from Namibia immediately and thus put an end to its occupation of the Territory;
………………………………………………………………………………………………
(2) . . . States Members of the United Nations are under obligation [p1092] to recognize the illegality of South Africa's presence in Namibia and the invalidity of its acts on behalf of or concerning Namibia, and to refrain from any acts and in particular any dealings with the Government of South Africa implying recognition of the legality of . . . such presence and administration" (I.C.J. Reports 1971, p. 58, para. 133).


Furthermore, the evidence indicates that the Botswana Government's preliminary contacts with the President of the United Nations Council for Namibia and the United Nations Commissioner for Namibia with a view to obtaining their approval prior to the Pretoria meeting of 19 December 1984 were not pursued further, and did not have the result sought by Botswana.

70. Nor does the Court need to examine any further Botswana's alternative argument that, even if the 1984-1985 "agreement" was invalid, it had been "adopted" by Namibia, first before the Joint Team of Technical Experts in 1994, then before the Court itself. The Court need only observe that no such "adoption" by Namibia has been established.

*

71. In the proceedings Namibia, too, invoked in support of its arguments the subsequent practice of the parties to the 1890 Treaty. In its Memorial it contended that this conduct

"is relevant to the present controversy in three distinct ways. In the first place, it corroborates the interpretation of the Treaty . . . Second, it gives rise to a second and entirely independent basis for Namibia's claim under the doctrines concerning acquisition of territory by prescription, acquiescence and recognition. Finally, the conduct of the parties shows that Namibia was in possession of the Island at the time of termination of colonial rule, a fact that is pertinent to the application of the principle of uti possidetis."

At the hearings Namibia stressed that "its primary claim is that its title is treaty-based", the claim "of prescription [being] asserted in the alternative"; and it argued in this regard that
"the very meaning of the ability to plead in the alternative is that each claim is to be considered in its own right, and no inference is to be taken against one claim because an inconsistent claim has been pleaded".

The subsequent practice relied on by Namibia consists of [p1093]

"the control and use of Kasikili Island by the Masubia of Caprivi, the exercise of jurisdiction over the Island by the Namibian governing authorities, and the silence by Botswana and its predecessors persisting for almost a century with full knowledge of the facts . . ."

Namibia contends that the members of the Masubia tribe - a people from the eastern part of the Caprivi Strip - had a "continued presence" on the Island at least between 1890 and the late 1940s. Citing various official documents, explorers' accounts and testimony of witnesses, it states that: "from the beginning of the colonial period at least, and probably a good deal further back than that, Kasikili Island was agricultural land cultivated by the people occupying what is now the Eastern Caprivi"; that "[t]heir occupation was continuous, exclusive and uninterrupted, in so far as the physical conditions of the Island allowed"; and that "Kasikili Island/Kasika [a Caprivi village] was a well organized village community, with a chief and at times with a school - its centre of gravity moving from one pole to the other in accordance with the dictates of the annual flood". According to Namibia, Germany from 1909, then its successors after 1915, incorporated the local institutions of the Masubia into the structure of colonial governance, using them as instruments for exercising their authority. The Masubia thus constituted a key component of the system of "indirect rule" which prevailed in the region. Namibia emphasizes that all these facts were known to the Bechuanaland authorities just across the Chobe, in Kasane, and that they made no objection or protest, at least until the late 1940s. And Namibia concludes that:

"the continued control and use of Kasikili Island by the people of the Eastern Caprivi, the exercise of jurisdiction over the Island by the governing authorities in the Caprivi Strip, and the continued silence of those on the other side of the Chobe . . . confirm the interpretation of the Treaty . . . [whereby] Article III . . . attributes Kasikili Island to Namibia".

72. Botswana, for its part, observes that

"the Namibian argument based upon subsequent conduct of the parties rests upon extraordinarily weak foundations, both in conceptual and in factual terms. The conceptual foundations are weak because in truth, the 'subsequent conduct' argument of Namibia is an argument grounded in acquisitive prescription. Thus, subsequent conduct, which relates to an existing legal instrument, is opposed to prescription, the purpose of which is to destroy and to supplant a pre-existing title."

It does not dispute that people from the Caprivi at times used the Island for agricultural purposes, but it stresses the sporadic nature of that use [p1094] and claims that the same applied to people living on the other side of the Chobe, in Bechuanaland. At all events, Botswana denies categorically that there was ever a permanent settlement or a village on Kasikili/Sedudu Island. And it concludes that the Eason Report of 1912, the diplomatic transactions of 1948 to 1951, and other pieces of evidence "all . . . establish conclusively that in administrative terms the Island always formed part of Botswana and its predecessor, the Bechuanaland Protectorate".

73. At this point in its Judgment, the Court will not examine Namibia's argument concerning prescription (see in this respect paragraphs 90-99 below). It will merely seek to ascertain whether the long-standing, unopposed, presence of Masubia tribespeople on Kasikili/Sedudu Island constitutes "subsequent practice in the application of the [1890] treaty which establishes the agreement of the parties regarding its interpretation" (1969 Vienna Convention on the Law of Treaties, Art. 31, para. 3 (b)).

74. To establish such practice, at least two criteria would have to be satisfied: first, that the occupation of the Island by the Masubia was linked to a belief on the part of the Caprivi authorities that the boundary laid down by the 1890 Treaty followed the southern channel of the Chobe; and, second, that the Bechuanaland authorities were fully aware of and accepted this as a confirmation of the Treaty boundary.

While it is true that the early maps of the region placed the boundary around Kasikili/Sedudu Island in the southern channel of the Chobe, none of them officially interpreted the 1890 Treaty (see paragraph 84 below), and the evidence would tend rather to suggest that the boundary line was shown as following the southern channel as a result of the intermittent presence on the Island of people from the Caprivi Strip. However, there is nothing that shows, in the opinion of the Court, that this presence was linked to territorial claims by the Caprivi authorities. It is, moreover, not uncommon for the inhabitants of border regions in Africa to traverse such borders for purposes of agriculture and grazing, without raising concern on the part of the authorities on either side of the border.

Furthermore, the Court is mindful that, already in 1912, when Great Britain was concerned with determining the boundary of the Bechuanaland Protectorate in the area in question, Captain Eason of the Bechuanaland police stated that "the North should be claimed as the main channel" of the Chobe around Kasikili/Sedudu Island (which, in view of the terms of the 1890 Treaty, placed the Island in Bechuanaland territory), while at the same time observing - without apparently seeing this as being in any way a problem - that "[t]he natives living at Kasika in German territory [we]re . . . growing crops on it" (see paragraph 53 above). There were similar statements in the Trollope-Redman Report of 19 January 1948, in which the two officials expressed the view that "the 'main channel' lies in the waterway which would include the island in question [p1095] in the Bechuanaland Protectorate"; at the same time, they noted that "use had been made of the Island by Eastern Caprivi Zipfel tribesmen" without objection from Bechuanaland (see paragraph 57 above). Finally, the joint survey report on the Chobe drawn up by South African and Botswanan experts on 15 July 1985 in the context of discussions on the location of the boundary around Kasikili/Sedudu Island noted that "livestock from Caprivi [we]re swum across the river when grazing on the Caprivi side was poor"; at the same time it suggested that "visits to the Island had, in recent years, become infrequent" (see paragraph 64 above). It would therefore seem that, as far as Bechuanaland, and subsequently Botswana, were concerned, the intermittent presence of the Masubia on the Island did not trouble anyone and was tolerated, not least because it did not appear to be connected with interpretation of the terms of the 1890 Treaty.

75. The Court concludes from the foregoing that the peaceful and public use of Kasikili/Sedudu Island, over a period of many years, by Masubia tribesmen from the Eastern Caprivi does not constitute "subsequent practice in the application of the [1890] treaty" within the meaning of Article 31, paragraph 3 (b), of the Vienna Convention on the Law of Treaties.

*

76. Botswana and Namibia also cite various other facts and incidents from which they seek to derive evidence of subsequent practice by the parties to the 1890 Treaty.

Thus Botswana asserts that Kasikili/Sedudu Island forms part of the Chobe National Park established in 1967 and, before that, was part of the Chobe Game Reserve created in 1960. According to Botswana, the use of the international boundary as the northern limit of the Game Reserve, and subsequently of the National Park, in the documents relating to their establishment necessarily had the effect of including Kasikili/Sedudu Island within them.

Botswana also relies on an affidavit and report by a witness concerning a visit to Kasane in 1972 by the then Botswana Head of State; from this it seeks to imply that he may have visited the Island as well, while at the same time acknowledging that there is no direct evidence that he actually did so.

77. Namibia, for its part, places reliance on an incident occurring during the same period. It states that three or four Caprivians were arrested on the Island by Botswana game wardens for poaching and released by a Botswana magistrate after a five-day detention, on the grounds that they had been arrested outside Botswana's jurisdiction. Namibia regards this as an acknowledgment by a Botswanan official of Namibian sovereignty over the Island. [p1096]

78. In the Court's view, these additional facts and incidents cited by the Parties cannot be regarded as representing "subsequent practice in the application of the [1890] treaty which establishes the agreement of the parties regarding its interpretation" (1969 Vienna Convention on the Law of Treaties, Art. 31, para. 3 (b)).

The documents establishing the Chobe Game Reserve and the Chobe National Park to which Botswana refers are internal documents, which, moreover, contain no express reference to Kasikili/Sedudu Island. Furthermore, Botswana itself recognizes that it has not been established that the Botswana Head of State visited the Island in 1972. As regards the incident cited by Namibia, it appears to be insufficiently proven.

*

79. The Court concludes from all of the foregoing that the subsequent practice of the parties to the 1890 Treaty did not result in any "agreement between the parties regarding the interpretation of the treaty or the application of its provisions", within the meaning of Article 31, paragraph 3 (a), of the 1969 Vienna Convention on the Law of Treaties, nor did it result in any "practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation", within the meaning of subparagraph (b) of that same provision.

80. However, the Court is bound to note that on at least three occasions, at different periods - in 1912, in 1948 and in 1985 - surveys carried out on the ground identified the channel of the Chobe to the north and west as the "main channel" of the river around Kasikili/Sedudu Island. The factual findings that the parties concerned arrived at separately in 1948 were expressed in concurrent terms in a joint report. In addition, the survey made in 1985 was conducted jointly by the parties then concerned. The factual findings made on these occasions were not, as such, disputed at the time. The Court finds that these facts, while not constituting subsequent practice by the parties in the interpretation of the 1890 Treaty, nevertheless support the conclusions which it has reached by interpreting Article III, paragraph 2, of the 1890 Treaty in accordance with the ordinary meaning to be given to its terms (see paragraph 41 above).

***

81. Both Parties have submitted in evidence in support of their respective positions a large number of maps, dating back as far as 1880. Most of the early maps are of German origin (in particular, the maps of Seiner (1909), Streitwolf (1910) and Frankenberg (1912)); there are, however, others of British origin (such as the Bradshaw map (1880), the map attached to the Eason Report (1912) and those contained in Colonial [p1097] Office Reports published between 1912 and 1915). The more recent maps include some prepared by the British (one of which, a map of Bechuanaland compiled by the War Office in 1933, became the basis for several subsequent maps), some produced by South Africa (including a 1949 map that served as an official map of the territory of South West Africa until Namibian independence), some published by Botswana after independence and one from the United Nations.

82. Namibia points out that the majority of the maps submitted in these proceedings, even those emanating from British colonial sources and intended to show the boundaries of Bechuanaland, tend to place the boundary around Kasikili/Sedudu Island in the southern channel. Namibia relies on this as "a specialized form of 'subsequent practice' and . . . also an aspect both of the exercise of jurisdiction and the acquiescence in it that matures into prescriptive title". Namibia places particular weight in this respect on the 1933 War Office map entitled "Bechuanaland Protectorate Sheet 2 1:500,000 GSGS 3915"; it claims that this map was in general use in Bechuanaland until 1965, and that, like other official maps dating from the last three decades of British rule in Bechuanaland, it excludes the Island from the territory of the Protectorate. Namibia also relies in this regard on the Court's decision in the Temple of Preah Vihear case, where it was held that acceptance by the parties to a treaty of a map showing a boundary may constitute an interpretation that departs from the express terms of that treaty (Judgment of 15 June 1962 (Merits), I.C.J. Reports 1962, pp. 6 et seq.). Namibia then concludes:

"This substantially unbroken practice by all three of the parties most closely concerned with the boundary between Botswana and Namibia - Germany, Great Britain and South Africa - strongly substantiates Namibia's contention as to the proper interpretation of Article III (2) of the 1890 Treaty. At the same time, it lends significant support to Namibia's claim of sovereignty over the Island by virtue of the doctrine of prescription and the principle of uti possidetis."

83. Botswana for its part places less reliance on maps, pointing out, inter alia, that most of the early maps show too little detail, or are too small in scale, to be of value in this case. Botswana asserts, however, that the available maps and sketches indicate that, from the time the Chobe was surveyed with any particularity by European explorers from the 1860s onwards, a north channel around the Island was known and regularly depicted. It cites the Bradshaw map of 1880, the Frankenberg map of 1912 and Captain Eason's map of 1912 as clearly indicating the presence of the northern and western channel in a manner closely similar to its present configuration. Botswana does not, however, attempt to [p1098] demonstrate that this places the boundary in the northern channel. Rather, its overall position is that the map evidence is far less consistent in placing the boundary in the southern channel than Namibia claims. At the hearings, Botswana argued that, when accuracy, the precise location of the boundary, and the fact of mere copying all are taken into account, one is left with three maps showing the boundary in the northern channel and only two in the southern channel (the 1933 British GSGS 3915 map, and the 1949 South African map). Botswana further asserts that there are technical problems with the latter two. As a consequence, it disputes Namibia's assertion that a preponderance of maps show the boundary to be in the southern channel. In Botswana's view, the Court should look for a map that shows agreement of the Parties - and that is to be found in the map attached to the Joint Survey of 1985 (see paragraph 64 above), which shows the boundary between South Africa and Botswana to lie in the northern channel of the Chobe.

84. The Court will begin by recalling what the Chamber dealing with the Frontier Dispute (Burkina Faso/Republic of Mali) case had to say on the evidentiary value of maps:

"maps merely constitute information which varies in accuracy from case to case; of themselves, and by virtue solely of their existence, they cannot constitute a territorial title, that is, a document endowed by international law with intrinsic legal force for the purpose of establishing territorial rights. Of course, in some cases maps may acquire such legal force, but where this is so the legal force does not arise solely from their intrinsic merits: it is because such maps fall into the category of physical expressions of the will of the State or States concerned. This is the case, for example, when maps are annexed to an official text of which they form an integral part. Except in this clearly defined case, maps are only extrinsic evidence of varying reliability or unreliability which may be used, along with other evidence of a circumstantial kind, to establish or reconstitute the real facts." (I.C.J. Reports 1986, p. 582, para. 54.)

As far as the present case is concerned, the Court notes that, according to Article III, paragraph 2, of the 1890 Treaty, "the course of the . . . boundary is traced in general accordance with a Map officially prepared for the British Government in 1889". No boundary line is drawn on this map, and it was not annexed to the 1890 Treaty, although a slightly later version of it was subsequently bound up with this Treaty in the British Foreign Office archive, as being the map alluded to in Article III, paragraph 2. There is also a map entitled "Map to Illustrate Article III of the Anglo-German Agreement of 1st July 1890", published in 1909 in the third edition of Hertslet's Map of Africa by Treaty. While the Parties dif-[p1099]fer in their view of the precise origin of this map, they apparently agree that it does not depict any relevant information concerning the channels around Kasikili/Sedudu Island or the location of the boundary. The Court notes that there was no map appended to the 1890 Treaty officially expressing the intentions of Germany and Great Britain with regard to the course of the boundary between their respective possessions in the area.

85. Certainly it is true, as the Court has already stated, that maps published subsequently to the 1890 Treaty, in so far as they showed the boundary at all, for a number of years placed it in the channel of the Chobe passing to the south of the Island (this applies particularly to the above-mentioned 1933 Bechuanaland map and 1949 South African map). However, there was no indication that the placement of the boundary in these maps was meant to be in accordance with Article III, paragraph 2, of the 1890 Treaty; rather, its origins may be linked to the use of the Island by the Masubia, which the Court has already rejected as evidence of practice reflecting subsequent interpretation of Article III, paragraph 2, by the parties to the 1890 Treaty (see paragraphs 74 and 75 above).

Moreover, once the issue of the boundary in the area had been raised in 1947-1948, the local Caprivi and Bechuanaland officials agreed that "the 'main Channel' d[id] not follow the waterway . . . usually shown on maps as the boundary between the two Territories" (Trollope/Redman Report, see paragraph 57 above). Those officials duly passed on their views to their respective superiors, and the Court finds it not without relevance in this regard that, in his letter of 26 January 1948 to the Bechuanaland Government Secretary in Mafeking, Mr. Redman stated that according to the 1890 Treaty the boundary must run along the northern channel, and that the map showing the boundary in the southern channel was "inaccurate and . . . probably drawn by some-one who had not examined the river to determine the main Channel" (see paragraph 58 above). It is clear from the subsequent correspondence between the South African and Bechuanaland authorities (see paragraphs 59 and 60 above) that their differing positions on the status of Kasikili Island and the location of the boundary had by 1951 hardened to the point where a local de facto arrangement became necessary. The Court considers that, in the light of that disagreement, there cannot be any question of the authorities concerned having accepted the maps then available in a manner capable of constituting "subsequent practice in the application of the [1890] treaty", still less recognition of the boundary shown on those maps. To the contrary, it appears to the Court that the parties largely ignored the maps, which they regarded as either accurate or inaccurate according to their respective positions on the course of the boundary. [p1100]

86. After Botswana's accession to independence, the relevant cartographic material shows greater variation, with certain maps (for example, the 1974 Botswana 1:50,000 map, the 1978 and 1982 official maps of the South African Ministry of Defence (JARIC) 1:100,000, the 1984 South Africa 1:50,000 map (the military intelligence version used by the South African army, with red overprint) and the 1984 Botswana 1:50,000 map) from then on placing the boundary around Kasikili/Sedudu Island in the Chobe's northern channel.

The Court will recall that this position was noted in the introduction to the 1985 Joint Survey Report and that the Botswana and South African experts concluded in this regard that "[t]he disparity in the depiction of the boundary between South African maps and those of Botswana ha[d] probably been a contributory factor in the recent border incident near Kasane" (see paragraph 64 above). The persistent uncertainty about the course of the boundary in the region - which led to the decision to undertake the 1985 Joint Survey - and the inconsistencies between maps preclude, in the Court's view, the possibility of there having been any kind of agreement, whether by way of interpretation of the 1890 Treaty or on any other basis, concerning the validity of any boundary depicted. The same is true of the subsequent period, when the dispute between Botswana and the newly-independent Namibia crystallized.

87. In view of the absence of any map officially reflecting the intentions of the parties to the 1890 Treaty and of any express or tacit agreement between them or their successors concerning the validity of the boundary depicted in a map (cf. Temple of Preah Vihear, Judgment, Merits, I.C.J. Reports 1962, pp. 33-35), and in the light of the uncertainty and inconsistency of the cartographic material submitted to it, the Court considers itself unable to draw conclusions from the map evidence produced in this case. That evidence cannot therefore "endors[e] a conclusion at which a court has arrived by other means unconnected with the maps" (Frontier Dispute (Burkina Faso/Republic of Mali), I.C.J. Reports 1986, p. 583, para. 56), nor can it alter the results of the Court's textual interpretation of the 1890 Treaty.

***

88. The foregoing interpretation of the relevant provisions of the 1890 Treaty leads the Court to conclude that the boundary between Botswana and Namibia around Kasikili/Sedudu Island provided for in this Treaty lies in the northern channel of the Chobe River.

89. According to the English text of the Treaty, this boundary follows the "centre" of the main channel; the German text uses the word "thalweg". The Court has already indicated that the parties to the 1890 Treaty intended these terms to be synonymous and that Botswana and Namibia [p1101] had not themselves expressed any real difference of opinion on this subject (see paragraph 25 above).

It is moreover clear from the travaux preparatoires of the Treaty (see paragraph 46 above) that there was an expectation of navigation on the Chobe by both contracting parties, and a common intention to exploit this possibility. Although, as has been explained above, the parties in 1890 used the terms "thalweg" and "centre of the channel" interchangeably, the former reflects more accurately the common intention to exploit navigation than does the latter. Accordingly, this is the term that the Court will consider determinative in Article III, paragraph 2.

Inasmuch as Botswana and Namibia agreed, in their replies to a question put by a Member of the Court, that the thalweg was formed by the line of deepest soundings, the Court concludes that the boundary follows that line in the northern channel around Kasikili/Sedudu Island.

***

90. Namibia, however, claims title to Kasikili/Sedudu Island, not only on the basis of the 1890 Treaty but also, in the alternative, on the basis of the doctrine of prescription. Namibia argues that
"by virtue of continuous and exclusive occupation and use of Kasikili Island and exercise of sovereign jurisdiction over it from the beginning of the century, with full knowledge, acceptance and acquiescence by the governing authorities in Bechuanaland and Botswana, Namibia has prescriptive title to the Island".

91. Botswana maintains that the Court cannot take into consideration Namibia's arguments relating to prescription and acquiescence as these are not included in the scope of the question submitted to it under the terms of the Special Agreement. According to Botswana, the purpose of that Agreement was to obtain from the Court determination of the boundary solely on the basis of the 1890 Treaty; invoking prescription would therefore involve adopting a totally different basis for determining the boundary. In support of its argument, Botswana points out in particular that the reference in the Special Agreement to the "rules and principles of international law" is "pleonastic", since an international agreement is normally interpreted taking into account any relevant rules of international law applicable in the relations between the parties. And it adds that:

"the alleged evidence of prescriptive title cannot be accepted as 'subsequent practice', because in such a hypothesis the working assumption is precisely the existence of a title of Botswana (or its predecessor) which allegedly is displaced by the operation of prescription". [p1102]

92. Namibia disputes this argument. It claims, for its part, that the wording of the question in the Special Agreement is clear and

"requires the Court to consider any evidence or submissions of the parties grounded in general rules and principles of international law equally with submissions based on the 1890 Treaty"

According to Namibia,

"Botswana's attempt to treat the reference to the 'rules and principles of international law' as if it were not included in the Special Agreement contravenes fundamental rules of treaty interpretation."

It stresses the contradictory nature of the position taken by Botswana, which, on the one hand, suggests that the expression "rules and principles of international law" covers only the rules and principles concerning treaty interpretation and, on the other, itself acknowledges that international law rules concerning treaty interpretation are comprehended in the first clause of the question referring to the 1890 Treaty. Namibia also reproaches Botswana for ignoring the dual nature of the argument it has put forward that

"either the subsequent conduct operates as a 'practice . . . which establishes the agreement of the parties regarding [the] interpretation' of the Treaty; or it stands as an independent root of title based on the doctrine of prescription and/or acquiescence".

93. The Court notes that under the terms of Article I of the Special Agreement, it is asked to determine the boundary between Namibia and Botswana around Kasikili/Sedudu Island and the legal status of the Island "on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law". Even if there had been no reference to the "rules and principles of international law", the Court would in any event have been entitled to apply the general rules of international treaty interpretation for the purposes of interpreting the 1890 Treaty. It can therefore be assumed that the reference expressly made, in this provision, to the "rules and principles of international law", if it is to be meaningful, signifies something else. In fact, the Court observes that the expression in question is very general and, if interpreted in its normal sense, could not refer solely to the rules and principles of treaty interpretation. The restrictive interpretation of this wording espoused by Botswana appears to be even less well-founded, in that Article III of the Special Agreement specifies that "the rules and principles of international law applicable to the dispute shall be those set forth in the provisions of Article 38, paragraph 1, of the Statute of the International Court of Justice". This wording shows that the Parties had no intention of confining the rules and principles of law applicable in this case solely to the rules and principles of international law relating to treaty interpretation. [p1103]

In the Court's view the Special Agreement, in referring to the "rules and principles of international law", not only authorizes the Court to interpret the 1890 Treaty in the light of those rules and principles but also to apply those rules and principles independently. The Court therefore considers that the Special Agreement does not preclude the Court from examining arguments relating to prescription put forward by Namibia.

94. According to Namibia, four conditions must be fulfilled to enable possession by a State to mature into a prescriptive title:

"1. The possession of the . . . state must be exercised a titre de souverain.

2. The possession must be peaceful and uninterrupted.

3. The possession must be public.

4. The possession must endure for a certain length of time."

Namibia alleges that in the present case Germany was in peaceful possession of the Island from before the beginning of the century and exercised sovereignty over it from the time of the establishment of the first colonial station in the Caprivi in 1909, all in full view and with the full knowledge of the Bechuanaland authorities at Kasane, only a kilometre or two from the Island. It states that this peaceful and public possession of the Island, a titre de souverain, was continued without interruption by Germany's successor until accession of the territory to independence. Finally, it notes that, after itself becoming independent in 1966, Botswana, which was aware of the facts, remained silent for almost two further decades.

In support of its allegations, Namibia emphasizes the importance of the presence on the Island of Masubia people from the Eastern Caprivi "from the beginning of the colonial period at least, and probably a good deal further back than that". It asserts that
"colonial records of German, British and South African authorities and the testimony of members of the Masubia community in the Kasika district before the JTTE [Joint Team of Technical Experts] [in 1994] conclusively show that the Masubia people of Eastern Caprivi have occupied and used Kasikili Island since time immemorial"

and points out that "the Masubia of the Caprivi Strip have used and occupied Kasikili Island as a part of their lands and their lives". Although Namibia admits that, in order to establish sovereignty by operation of prescription, acquiescence and recognition, it must show more than the use of the disputed territory by private individuals for their private ends, it maintains that:

"Namibia's predecessors exercised continuous authority and jurisdiction over Kasikili Island. From 1909 until the termination of the Mandate in 1966, German, Bechuanaland and South African officials consistently governed the Eastern Caprivi through Masubia chiefs, whose jurisdiction extended to Kasikili Island. After termina-[p1104]tion of the Mandate, South Africa, under pressure from the liberation struggle, increasingly exerted direct power in the area until Namibia's independence on 21 March 1990."

Namibia states that the authority exercised over Kasikili Island by its predecessors was implemented

"for the most part . . . through the modality of 'indirect rule,' using the chiefs and political institutions of the Masubia to carry out the directives of the ruling power, under the control and supervision of officials of that power"

and that

"although indirect rule was manifested in a variety of ways, its essence was that the acts of administration of the colonial authorities and those of the traditional authorities were acts of a single entity: the colonial government".

According to Namibia, this situation

"prevailed without any objection, reservation or protest from Botswana or its predecessors in interest for almost a century until 1984, when Botswana first made formal claim to the Island in private meetings with the South African government".

In support of its argument concerning prescription, Namibia also invokes the incident between a patrol boat of the South African Defence Force and a unit of the Botswana Defence Force in October 1984, which, in its view, indicated that South Africa was exercising jurisdiction over the Island by conducting military patrols in the southern channel. It also refers to a number of official maps of the Caprivi portraying the Island as part of Namibia from the beginning of the century, as well as to the concurrence of the British authorities.

95. Although it considers the doctrine of prescription inapplicable in this case for the reasons referred to earlier, Botswana accepts the criteria for acquiring prescriptive title as set out by Namibia; it argues, however, that those criteria have not been satisfied by Namibia and its predecessors. Botswana asserts, in substance, that "there is no credible evidence that either Namibia or its predecessors exercised State authority in respect of Kasikili/Sedudu" and that even if peaceful, public and continuous possession of the Island by the people of Caprivi had been proved, it could not have been a titre de souverain.

Botswana does not dispute that people from the Caprivi used Kasikili/Sedudu Island at times for agricultural purposes; but it maintains that so did people living on the other side of the Chobe, in Bechuanaland, and [p1105] denies that there was ever any village or permanent settlement on the Island. Botswana emphasizes that in any case "the acts of private persons cannot generate title unless those acts are subsequently ratified by the State"; that no evidence has been offered to the effect that the Masubia chiefs had authority to engage in title-generating activities for the benefit of Germany or its successors; and that evidence is also lacking of any "genuine belief" in the existence of title on the part of Germany and its successors.

With regard to patrolling by South Africa, Botswana asserts that this involved at the very most anti-guerilla operations, which cannot be classified as an exercise of jurisdiction; it claims that the incident of 1984 could not constitute evidence of peaceful possession for the purposes of prescription. Finally, Botswana denies that the map evidence has any value in this case; it maintains that this evidence is contradictory and confused and that the authorities of Bechuanaland and Botswana never recognized or acquiesced in the maps showing the boundary in the southern channel.

96. The Parties agree between themselves that acquisitive prescription is recognized in international law and they further agree on the conditions under which title to territory may be acquired by prescription, but their views differ on whether those conditions are satisfied in this case. Their disagreement relates primarily to the legal inferences which may be drawn from the presence on Kasikili/Sedudu Island of the Masubia of Eastern Caprivi: while Namibia bases its argument primarily on that presence, considered in the light of the concept of "indirect rule", to claim that its predecessors exercised title-generating State authority over the Island, Botswana sees this as simply a "private" activity, without any relevance in the eyes of international law.

97. For present purposes, the Court need not concern itself with the status of acquisitive prescription in international law or with the conditions for acquiring title to territory by prescription. It considers, for the reasons set out below, that the conditions cited by Namibia itself are not satisfied in this case and that Namibia's argument on acquisitive prescription therefore cannot be accepted.

98. The Court has already considered the presence of the Masubia on Kasikili/Sedudu Island when it examined the subsequent practice of the parties to the 1890 Treaty (see paragraphs 71 et seq. above).

It follows from this examination that even if links of allegiance may have existed between the Masubia and the Caprivi authorities, it has not been established that the members of this tribe occupied the Island a titre de souverain, i.e., that they were exercising functions of State authority there on behalf of those authorities. Indeed, the evidence shows that the Masubia used the Island intermittently, according to the seasons and [p1106] their needs, for exclusively agricultural purposes; this use, which began prior to the establishment of any colonial administration in the Caprivi Strip, seems to have subsequently continued without being linked to territorial claims on the part of the Authority administering the Caprivi. Admittedly, when, in 1947-1948, the question of the boundary in the region arose for the first time between the local authorities of Bechuanaland Protectorate and of South Africa, the Chobe's "main channel" around the Island was said to be the northern channel, but the South African authorities relied on the presence of the Masubia on the Island in order to maintain that they had title based on prescription. However, from then on the Bechuanaland authorities took the position that the boundary was located in the northern channel and that the Island was part of the Protectorate; after some hesitation, they declined to satisfy South Africa's claims to the Island, while at the same time recognizing the need to protect the interests of the Caprivi tribes. The Court infers from this, first, that for Bechuanaland, the activities of the Masubia on the Island were an independent issue from that of title to the Island and, second, that, as soon as South Africa officially claimed title, Bechuanaland did not accept that claim, which precluded acquiescence on its part.

99. In the Court's view, Namibia has not established with the necessary degree of precision and certainty that acts of State authority capable of providing alternative justification for prescriptive title, in accordance with the conditions set out by Namibia, were carried out by its predecessors or by itself with regard to Kasikili/Sedudu Island. The Court has already observed above that it is unable to draw conclusions from the map evidence produced in this case (see paragraph 87 above). Nor in its view, can conclusions be drawn from the incident involving Botswana and South African defence forces in the channel to the south of the Island in October 1984.

***

100. The Court's interpretation of Article III, paragraph 2, of the 1890 Treaty has led it to conclude that the boundary between Botswana and Namibia around Kasikili/Sedudu Island follows the line of deepest soundings in the northern channel of the Chobe.

101. Since the Court has not accepted Namibia's argument on prescription, it follows for this reason also that Kasikili/Sedudu Island forms part of the territory of Botswana.

102. The Court observes, however, that the Kasane Communique of 24 May 1992 records that the Presidents of Namibia and Botswana agreed and resolved that:

"(c) existing social interaction between the people of Namibia and Botswana should continue;

(d) the economic activities such as fishing shall continue on the understanding that fishing nets should not be laid across the river; [p1107]

(e) navigation should remain unimpeded including free movement of tourists".

The Court further observes that in explanation and in pursuance of the foregoing agreement, Botswana stated at the oral hearings:
"Botswana's policy is to allow free navigation, including unimpeded movement of tourist boats even in the southern channel. This policy applies to boats owned by Namibian tourist operators as well. The only requirement is that all tourist boats should be registered. This requirement is meant solely to prevent the danger of environmental pollution of the Chobe River. Experience has shown that some tourist boat operators tended to transport their boats from Okavango waters, infested with river weeds, down to the Chobe River, without applying for a trans-zonal permit. The Department of Water Affairs, and not the Botswana Defence Force, is responsible for enforcing the policy on anti-pollution of the river waters.

Botswana's policy on free navigation, including the free movement of tourist boats, was set out in paragraph (e) of the Kasane Communique . . . Since the Kasane Communique was agreed in May 1992, there has been no complaint from the Namibian Government that Botswana ever breached paragraph (e) of the Communique which guarantees unimpeded navigation."

Subsequently, Botswana added that:

"Botswana also wishes to reiterate that tourist boats from Namibia are free to travel in the southern channel. The only requirement is that all such boats should be registered, in order to control noxious aquatic weeds . . . this requirement is backed by proper legislation, namely, the Laws of Botswana Aquatic Weeds (Control) Act, which commenced in December 1971. The provisions of this Act were later discussed with, and endorsed by the Water Affairs Department of Namibia. Since then, Namibian tourist boat operators have registered as many as 53 boats, to travel in Botswanan waters of the Chobe River. These 53 Namibian boats are permitted to navigate in the southern channel, like any others that have been licensed."

103. The Court, which by the terms of the Joint Agreement between the Parties is empowered to determine the legal status of Kasikili/Sedudu Island concludes, in the light of the above-mentioned provisions of the Kasane Communique, and in particular of its subparagraph (e) and the interpretation of that subparagraph given before it in this case, that the Parties have undertaken to one another that there shall be unimpeded [p1108] navigation for craft of their nationals and flags in the channels of Kasikili/Sedudu Island. As a result, in the southern channel of Kasikili/Sedudu Island, the nationals of Namibia, and vessels flying its flag, are entitled to, and shall enjoy, a treatment equal to that accorded by Botswana to its own nationals and to vessels flying its own flag. Nationals of the two States, and vessels, whether flying the flag of Botswana or of Namibia, shall be subject to the same conditions as regards navigation and environmental protection. In the northern channel, each Party shall likewise accord the nationals of, and vessels flying the flag of, the other, equal national treatment.


***

104. For these reasons,

THE COURT,

(1) By eleven votes to four,

Finds that the boundary between the Republic of Botswana and the Republic of Namibia follows the line of deepest soundings in the northern channel of the Chobe River around Kasikili/Sedudu Island;

IN FAVOUR: President Schwebel; Judges Oda, Bedjaoui, Guillaume, Ranjeva, Herczegh, Shi, Koroma, Vereshchetin, Higgins, Kooijmans;

AGAINST: Vice-President Weeramantry; Judges Fleischhauer, Parra-Aranguren, Rezek.

(2) By eleven votes to four,

Finds that Kasikili/Sedudu Island forms part of the territory of the Republic of Botswana;

IN FAVOUR: President Schwebel; Judges Oda, Bedjaoui, Guillaume, Ranjeva, Herczegh, Shi, Koroma, Vereshchetin, Higgins, Kooijmans;

AGAINST: Vice-President Weeramantry; Judges Fleischhauer, Parra-Aranguren, Rezek.

(3) Unanimously,

Finds that, in the two channels around Kasikili/Sedudu Island, the nationals of, and vessels flying the flags of, the Republic of Botswana and the Republic of Namibia shall enjoy equal national treatment.

Done in English and in French, the English text being authoritative, at the Peace Palace, The Hague, this thirteenth day of December one thousand nine hundred and ninety-nine in three copies, one of which [p1109] will be placed in the archives of the Court and the others transmitted to the Government of the Republic of Botswana and the Government of the Republic of Namibia, respectively.

(Signed) Stephen M. Schwebel,
President.

(Signed) Eduardo Valencia-Ospina,
Registrar.

Judges RANJEVA, KOROMA and HIGGINS append declarations to the Judgment of the Court.

Judges ODA and KOOIJMANS append separate opinions to the Judgment of the Court.

Vice-President WEERAMANTRY, Judges FLEISCHHAUER, PARRA-ARANGUREN and REZEK append dissenting opinions to the Judgment of the Court.

(Initialled) S.M.S.

(Initialled) E.V.O. [p1110]


DECLARATION OF JUDGE RANJEVA

[Translation ]

First, I should like to explain how I interpret the reply to Article I of the Special Agreement concerning paragraphs 2 and 3 of the operative part of the Judgment relating to the status of Kasikili/Sedudu Island:

1. Given its effect, in terms of allocation of territory, the Judgment's choice of the northern channel as the main channel is the least improbable solution, in the absence of a systematic comparison of the two navigation channels; this is the reason for the finding that Kasikili/ Sedudu Island forms part of the territory of Botswana.

2. The Kasane Communique created legal obligations for the two States parties to the dispute with regard to the enjoyment and exercise of rights by their nationals in the relevant area; in addition to navigation and fishing rights in the channel, there is a right of free access to the surrounding waters and to the territory of Kasikili/Sedudu Island.

Further, as regards the presence of the Masubia on Kasikili/Sedudu Island, the statement in paragraph 98 of the Judgment that:

"even if links of allegiance may have existed between the Masubia and the Caprivi authorities, it has not been established that the members of this tribe occupied the Island α litre de souverain, i.e., that they were exercising functions of State authority there on behalf of those authorities"

is not of general import and relates only to the particular circumstances of the present case.

(Signed) Raymond RANJEVA. [p1111]



DECLARATION OF JUDGE KOROMA

Decision by Namibia and Botswana to bring dispute to Court by Special Agreement.

Possible interpretations of 1890 Anglo-German Agreement — Choice of one such interpretation by the Court — Recognition and application of principle of uti possidetis as part of the African legal order.

Kasane Communique as basis of shared use of river also in accordance with contemporary legal principles of international watercourses.

Legal effect of Judgment on boundary and status of Island.

The Governments of Namibia and Botswana are to be commended for their decision to entrust their dispute to the Court for peaceful settlement. Although the dispute involves the location of a riverine boundary between the two States within one specific area and the determination of the legal status of a relatively small island within that area, the fact that the Parties decided on the basis of a Special Agreement to bring the matter to the Court is a measure of the importance they attach to the territory in dispute and to their mutual relations.

It has not been unknown for similar disputes to be the source of serious tension between two States or even to give rise to armed conflict. Rather than that, the two neighbouring States elected by means of a Special Agreement to request the Court to determine, on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law, their boundary around Kasikili/Sedudu Island and the legal status of the Island.

It is inevitable that the Court, in performing its judicial task and applying the provisions of the 1890 Treaty, would choose one of a number of possible interpretations of the Treaty as representing the shared intention of the Parties and in the light of the material before it — both historical and contemporary — to identify and locate the boundary prescribed therein.

At the same time, in making these findings, the Court, recognizing the need for stable boundaries, applied the principle of uti possidetis — an important principle recognized by African States as part of the African legal order according to which African States' boundaries should follow those inherited at independence.

Accordingly, the Court's Judgment should invest the boundary as determined, as well as the status of the Island, with the necessary legal validity which they had been accorded by the 1890 Treaty and which the Parties to the Special Agreement have asked the Court to determine.
[p1112]
Also in the light of its judicial function, and taking into account the Kasane Communiquι and the official interpretation given to that Communiquι before the Court, the latter reached the decision that, in the two channels around the Island, the nationals of, and boats flying the flags of, the Republic of Botswana and the Republic of Namibia shall enjoy equal treatment in the waters of the other State. This important finding by the Court should not be regarded as extra-legal but finds a solid basis in international law and in the jurisprudence of the Court. In international law, control by a riparian State of its own fluvial territory is matched by that of free navigation. Thus, while respecting the terms of a Special Agreement empowering the Court to determine the riparian boundary between two States, the Court is entitled to lay down terms which not only determine the boundary as such but would contribute to the peace and stability between the two States. The Judgment, in my view, serves this purpose as well.

(Signed) Abdul G. KOROMA. [p1113]


DECLARATION OF JUDGE HIGGINS

The task of the Court — Temporal issues — Relevance of mistake as regards navigability — Realism in application of treaty terms — Importance of visible physical features.

1. At paragraph 28 of its Judgment the Court states that it is interpreting words in a treaty to give them their ordinary meaning; and that this is what it is doing in determining the meaning of "main channel" by "reference to the most commonly used criteria in international law". I find this somewhat fanciful. In my view, although there are commonly used international law criteria for understanding, for example, the term "thalweg", the same is not true for the term "main channel". And it seems that no "ordinary meaning" of this term exists, either in international law or in hydrology, which allows the Court to suppose that it is engaging in such an exercise. The analysis on which the Court has embarked is in reality far from an interpretation of words by reference to their "ordinary meaning". The Court is really doing something rather different. It is applying a somewhat general term, decided upon by the parties in 1890, to a geographic and hydrographic situation much better understood today.

2. The term "the main channel" is not a "generic term" (cf. Aegean Sea Continental Shelf, I.C.J. Reports 1978, p. 32, para. 77) — that is to say, a known legal term, whose content the parties expected would change through time. Rather, we find ourselves closer to the situation of the Arbitral Tribunal in the Laguna del Desierto case of 1994 (see paragraph 20 of the Court's Judgment). The Tribunal there stated that it could not accept Chile's argument:

"that to apply the 1902 Award in light of geographical knowledge acquired subsequently would be equivalent to its revision through the retrospective consideration of new facts. The 1902 Award defined, in the sector with which this Arbitration is concerned, a frontier which follows a natural feature that, as such, does not depend on accurate knowledge of the area but on its true configuration. The ground remains as it has always been . . . [t]his Judgment is . . . faithfully applying the provisions of the Award of 1902." {International Law Reports, Vol. 113, p. 76, para. 157.) [p1114]

This dictum retains a certain relevance, notwithstanding that the fact situation in the Laguna case is somewhat different from ours.

3. The Court is indeed, for this particular task, entitled to look at all the criteria the Parties have suggested as relevant. This is not to discover a mythical "ordinary meaning" within the Treaty, but rather because the general terminology chosen long ago falls to be decided today. To use contemporary knowledge and scientific data to assist in fulfilling that task is not at all inconsistent with the intertemporal rule in the Island of Palmas Award, which was concerned with the legal rules applicable to title to territory and not with identification, through the legal technique of evaluating evidence, of a chosen term.

4. At the same time, we must never lose sight of the fact that we are seeking to give flesh to the intention of the parties, expressed in generalized terms in 1890. We must trace a thread back to this point of departure. We should not, as the Court appears at times to be doing, decide what in abstracto the term "the main channel" might today mean, by a mechanistic appreciation of relevant indicia. Rather, our task is to decide what general idea the parties had in mind, and then make reality of that general idea through the use of contemporary knowledge.

5. Although the travaux prιparatoires have little to say, our general knowledge of the time suggests that two things were important to Britain and Germany as they concluded the Treaty of 1890. The first was that they sought a clear delimitation of their spheres of interest in (inter alia) the north eastern sector of South West Africa. The second was that they supposed that this could be done in a way as to allow to each party the possibility of riverine access to the Zambezi.

6. We know now that the assumptions as to navigability were mistaken. For its greater part the River Chobe is not navigable; no further engineering works have been able to bring into being access to the Zambezi and indeed, even in the area around Sedudu-Kasikili, there can only be navigation by vessels of very shallow draught. But the law of mistake, and particularly Article 48 of the Vienna Convention on the Law of Treaties, has no place in all of this, because it cannot plausibly be suggested that the 1890 Treaty would not have been concluded if this error had been known — nor even that the words that exercise us here would have been in a different formulation whose content we can now discern. A fully contextual application today of treaty terms selected in 1890 should not place emphasis on elements that, to be sure, have a theoretical relevance but none in the particular realities of the case. Thus in my view little account should thus today be taken of factors that go [p1115] mostly to concepts of navigability when we seek to determine which is the main channel. Nor does the fact of important contemporary tourist boating in the southern channel guide us as to which today should be designated as "the main channel", as navigation around the Island was not at all what the parties were concerned with.

7. I add, to make my position clear, that I agree with all the Judgment has to say at paragraphs 47 to 63, regarding the legal significance of the diplomatic history of the matter. However — and unlike the Court — I equally place no reliance at all in the facts said to be found by Eason, Trollope and Redman, whose methodology is not fully known to us and who were preoccupied with the question of depth; nor do I think it useful to accept as "facts" findings of the Joint Team of Experts, such "facts" not having been accepted by South Africa as determinative of the under-lying legal issue.

8. By contrast, emphasis should be given to the main, and still realistic, desire of the parties to choose the channel that would most clearly mark the limits of their interests. Thus, in my view a considerable importance has thus to be given to the visible physical distinctions between the two channels. Whether the waters in them do or do not originate in the Chobe itself, whether they are stagnant or fresh, whether one channel is fractionally deeper than another, seems to me to matter very little.

9. From this perspective two competing elements immediately come into play. The first is that the Chobe Ridge could be said to play an important role in marking a clearly visible frontier, throughout the year. But the second, perhaps yet more significant, is that, year round, taking one season with another (which seems to me more relevant to the task in hand than low water mark reliance), it is the north that appears in the aerial photography and satellite imagery to be the broader and more important channel.
10. Not without some difficulty, I have therefore come to the view that the main channel — in the generalized sense intended by the parties — lies in the north.

(Signed) Rosalyn HIGGINS. [p1116]



SEPARATE OPINION OF JUDGE ODA

TABLE OF CONTENTS

 

 

Paragraphs

I.  Introductory Remarks

1-8

 

 

II.  The Case Presented to the Court by Means of a Compromis

9-21

 

 

(1) Lack of clarity in the compromis

9-10

(2) The background to the filing of the case at the Court

11-17

(3) Further comments on the lack of clarity in the compromis

18-21

 

 

III. "On the Basis of the 1890 Anglo-German Treaty"

22-33

 

 

(1) Introduction

22

(2) The significance of the 1890 Anglo-German Treaty

23-27

(3) The meaning of "main channel" in the 1890 Treaty

28-32

(4) How has the "main channel" been recognized on various occasions in the past?

33

 

 

IV. "On the Basis of the Rules and Principles of International Law"

34-36

 

 

V.  How the "Main Channel" of the Chobe River Was Recognized in Past Practice and How That Would Assist the Court to Determine the Boundary along the Chobe River

37-59

 

 

(1) Introduction

37-38

(2) Treatment of maps

39-41

(3) The geographical conditions of the area surrounding Kasikili/ Sedudu Island and the political and social situation of the Island up to middle of this century

42-47

(4) The confrontation in the 1940s between the authorities of the Union of South Africa and the British High Commis­sioner's Office for the Bechuanaland Protectorate

48-56

(5) The occurrence of incidents in 1984 after Botswana's inde­pendence in 1966, and the joint survey which followed

57-58

(6) What does the past practice indicate?

59

 

 

VI.  Conclusion

60-63


[p1117]

I. INTRODUCTORY REMARKS

1. I voted in favour of the Court's Judgment, as I support its determination that the northern channel of the Chobe River constitutes the boundary between Botswana and Namibia, and that Kasikili/Sedudu Island forms part of the territory of Botswana.

2. Although I voted in favour of subparagraph (3) of the operative part, I felt that this matter, which was not in fact presented to the Court in the compromis and was not indicated in the submissions of either Party, need not be dealt with in the operative part of the Judgment, since it had already been sufficiently discussed in the prior sections of the Judgment devoted to the reasoning (paras. 102 and 103).

*

3. I must say, to my great regret, that I fail to understand properly the sequence of logic followed by the Court in this Judgment. The reasoning which led the Court to its decision does not necessarily reflect my own understanding of the case as a whole. I could even say that I am totally lost when reading the Judgment and I quote an illustration below:

"41. For the foregoing reasons [in the part above, the Court mentions the natural physical conditions of the channel], the Court concludes that, in accordance with the ordinary meaning of the terms that appear in the pertinent provision of the 1890 Treaty, the northern channel of the River Chobe around Kasikili/Sedudu Island must be regarded as its main channel."

"79. The Court concludes from all of the foregoing that the subsequent practice of the parties to the 1890 Treaty did not result in any 'agreement between the parties regarding the interpretation of the treaty or the application of its provisions', within the meaning of Article 31, paragraph 3 (a), of the 1969 Vienna Convention on the Law of Treaties, nor did it result in any 'practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation', within the meaning of subparagraph (b) of that same provision."

"80. . . . The Court finds that these facts, while not constituting subsequent practice by the parties in the interpretation of the 1890 Treaty, nevertheless support the conclusions which it has reached by interpreting Article III, paragraph 2, of the 1890 Treaty in accordance with the ordinary meaning to be given to its terms (see paragraph 41 above)."

"88. The foregoing interpretation of the relevant provisions of the 1890 Treaty leads the Court to conclude that the boundary between Botswana and Namibia around Kasikili/Sedudu Island provided for in this Treaty lies in the northern channel of the Chobe River." [p1118]

4. It is most important to note that this case is not brought by unilateral application by one of the Parties to this dispute in order to seek clarification of international law governing the boundary between the two States in question and the legal status of Kasikili/Sedudu Island by applying the 1969 Vienna Convention on the Law of Treaties. This is a case brought by means of a compromis, by which the Parties seek to have the Court determine the boundary and the legal status of the Island on the basis of the criteria which the Parties jointly wish to be applied.

It appears to me that the Judgment places excessive reliance upon the Vienna Convention on the Law of Treaties for the purpose of the Court's interpretation of the 1890 Anglo-German Treaty. The Parties to this case certainly agreed that the Court should be asked to determine the bound-ary on the basis of the 1890 Treaty — and it should again be pointed out quite categorically that Botswana and Namibia are not parties to that Treaty — but the Court has not been asked to interpret the 1890 Treaty itself. The Judgment quotes Article 31 (General rule of interpretation) of the 1969 Vienna Convention on the Law of Treaties almost in its entirety. Reference is made in the Judgment to this provision of the Vienna Convention at least eleven times. Although I am fully aware that the Vienna Convention reflects customary international law, it should, however, be noted, as the Judgment correctly points out in its paragraph 18, that this Convention "applies only to treaties which are concluded by States after the entry into force of the present Convention with regard to such States" (Art. 4). In fact, the Convention came into force in 1980. This case does not appear to me to be one related to the application of the Vienna Convention.

5. I gain the impression that the Parties to this case, Botswana and Namibia, as well as the Court have devoted much time and energy to interpreting the German term "Thalweg", which, as the Judgment itself admits, was simply a translation of the English word "centre" (Judgment, para. 46). The Court was requested to determine where — whether in the northern or the southern channel of the Chobe River — the "main channel", as referred to in Article III (2) of the 1890 Treaty, and hence the boundary between Botswana and Namibia, should be considered to lie. In this respect, I fail to understand why the operative part of the Judgment states that the boundary follows "the line of deepest soundings" in the northern channel of the Chobe River (Judgment, para. 104 (1)). As proposed by the Parties during the oral hearings, the Court has employed the phrase "the line of deepest soundings" as a substitute for the word "Thalweg" (Judgment, para. 89). It would, in my view, have been sufficient for the Court to state simply — and nothing more — which of the two channels, the northern or the southern, constitutes the "main channel", namely the boundary in the Chobe River separating Botswana and Namibia.

6. It seems to be very important to make a distinction between, on the [p1119] one hand, the criteria to be employed in order to determine the "main" channel in general terms and, on the other, a decision applying those criteria to a specific geographical situation. The criteria for determining the "main" channel may well be settled by law, with the assistance of scientific knowledge, but the determination of the "main channel" as a boundary by employing the said criteria, in any specific geographical situation, is far from being a legal function. I would recall that, at the time of the meeting in Kasane of the Presidents of Botswana and Namibia in May 1992, the two States tried to settle the matter as a technical problem that could be solved by the expertise of technical experts (see paragraphs 13 and 14 of this opinion). The Judgment deals with these two matters in its paragraphs 20 to 40 and attempts to rule on them, relying only on the information given in the written and oral pleadings by the respective Parties, but without the benefit of objective scientific knowledge, which it could have obtained itself but chose not to.
7. The Judgment refers to various acts or conduct relating to the Chobe River and to certain survey reports concerning the River produced by various authorities. I accept that these facts and the survey reports are extremely important for the Court's consideration of the matter. However, I am unable to accept the Court's position that such facts and reports could be considered only as possible evidence of "any subsequent agreement between the parties regarding the interpretation of the treaty or the application of its provisions" or "any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation" within the meaning of Article 31, paragraph 3, of the Vienna Convention on the Law of Treaties, to be taken into account when interpreting the 1890 Anglo-German Treaty. The Court, after a lengthy analysis (paras. 47 to 70), comes to the conclusion that the facts and documents in question cannot be regarded as constituting "any subsequent agreement" or "any subsequent practice" to be used for the interpretation of the 1890 Treaty, although the Court ultimately found that these facts "nevertheless support the conclusions which it has reached by interpreting Article III, paragraph 2, of the 1890 Treaty in accordance with the ordinary meaning to be given to its terms" (para. 80). I would rather suggest that these facts and documents should be considered at their face value, as historical background to the present case but without having any bearing on the provisions of the Vienna Convention, in order to assist the Court in determining the boundary.

8. As my position in regard to this case differs somewhat from the views that have led the Court to its Judgment, I feel that I should sketch out the view that I take of it. [p1120]

II. The Case Presented to the Court by Means of a Compromis

(I) Lack of Clarity in the Compromis

9. I first ask myself what is the subject-matter of the "case" presented by the compromis between Botswana and Namibia pursuant to Article 36, paragraph 1, of the Statute.

In the second paragraph of the Preamble to the compromis, Botswana and Namibia both state that "a dispute exists between [Botswana] and [Namibia] relative to the boundary around Kasikili/Sedudu Island" (emphasis added), but in Article I they request the Court to determine not only "the boundary between Namibia and Botswana around Kasikili/ Sedudu Island" (emphasis added) but also "the legal status of the island" (emphasis added). It might be contended that the determination of the legal status of Kasikili/Sedudu Island would in fact have the same effect as the determination of the boundary between Botswana and Namibia in the area around Kasikili/Sedudu Island. It would seem that both States had originally thought that the determination of the boundary in the Chobe River would automatically determine the legal status of Kasikili/ Sedudu Island.

The determination of the boundary in the Chobe River would indeed result in the determination of the legal status of Kasikili/Sedudu Island. Conversely, a determination of the legal status of Kasikili/Sedudu Island would also result in the determination of the boundary. However, the solutions to these two issues may not necessarily be the same. It appears that the two States, whether intentionally or unintentionally, have radically changed their approach, in that an issue relating to the river boundary in the Chobe River has now become an issue also over the legal status of Kasikili/Sedudu Island.

At all events, the Court should not have overlooked the contradiction between these two different theses: on the one hand, the definition of the dispute, including only matters relating to a boundary as defined in the Preamble to the compromis, and on the other hand, the request contained in Article 1 of the compromis concerning the boundary in the Chobe River and the legal status of Kasikili/Sedudu Island.

10. The Court is requested "to determine ... on the basis of the [1890] Anglo-German Treaty . . . and the rules and principles of international law" (compromis, Art. I). The words "rules and principles of international law" are understood by the Parties to mean "those [as] set forth in the provisions of Article 38, paragraph 1, of the Statute of the International Court of Justice" (compromis, Art. Ill), namely, "the general principles of law recognized by civilized nations" (Statute, Art. 38, para. 1).

In my view these two bases on which to proceed may be mutually contradictory, or even mutually exclusive. If the Court takes the 1890 Anglo-German Treaty as its basis, it cannot at the same time take into account "the rules and principles of international law", which the Parties [p1121] interpret as being "the general principles of law recognized by civilized nations".

If we confine ourselves to the first question, relating to the boundary in the Chobe River between Botswana and Namibia in the area of Kasikili/ Sedudu Island, the 1890 Anglo-German Treaty can be used as a basis for the Court's determination. If, however, we deal with the second question, namely the determination of the legal status of Kasikili/Sedudu Island, the "rules and principles of international law" in general may be thought to apply. In sum, the two bases to be applied by the Court cannot be considered as supplementary or harmonious, for they are mutually contradictory.

I assume that both countries thought a boundary could be drawn on the basis of the 1890 Anglo-German Treaty, and that for this purpose the determination of the "main channel" of the Chobe River provided for in the 1890 Treaty would be the cornerstone of the case. However, given that the two States changed their positions on the matter, making the legal status of Kasikili/Sedudu Island one of the two main issues of the "case", a conclusion cannot be reached simply from an interpretation of what constitutes the "main channel" of the Chobe River but must also involve application of "the rules and principles of international law" (interpreted by the Parties as being the general principles of law recognized by civilized nations).

This change in the Parties' approach to the issues can be seen from the account of the background to events that I give in the next section.

(2) The Background to the Filing of the Case at the Court

11. The Court is faced with a "case" between Botswana (which gained independence from the former British Protectorate Bechuanaland in 1966) and Namibia (which had been under the administration of the United Nations Council for Namibia until 1990) concerning the geography of Kasikili/Sedudu Island in the Chobe River and the surrounding area. Let me examine how this "case", submitted under Article 36, paragraph 1, of the Statute, has arisen between these two States.

On gaining its independence in 1966, Botswana took over the area, which since 1886 had been under the authority of the British Protectorate of Bechuanaland (Judgment, para. 14). On independence in 1990, the territory of Namibia remained identical to that of South West Africa — the 1881 German sphere of influence (ibid.). Upon the outbreak of the First World War, the area under German influence, known today as the territory of Namibia, was occupied and governed by British forces from Southern Rhodesia. This area was then transferred to the mandatory territory under the Union of South Africa in the League of Nations system in 1919 and was, from 1967, placed under the administration of the United Nations Council for Namibia, though de facto control by the Republic of South Africa continued until 1990. There has [p1122]
been no difference of views between Botswana and Namibia on these facts.

12. If there was any territorial issue between the two States, Botswana and Namibia, concerning this area in the region of the Chobe River, it originated from the fact that Namibia, after its independence in 1990, sent armed forces to Kasikili/Sedudu Island in 1991 and that, also in 1991, Botswana raised its national flag over the Island.

It would appear from these two incidents that in 1991 each of the two States, Botswana and Namibia, thought that Kasikili/Sedudu Island formed part of its sovereign territory. However, neither State expressed the view that there had been any violation of sovereignty by the other State. If any immediate negotiation did take place between the two countries on this issue, it was not reported.

13. It was as a result of the above incidents that the two States' difference of views regarding the territoriality of Kasikili/Sedudu Island came to light.

The Presidents of Botswana and Namibia met on 24 May 1992 at Kas-ane, thanks to the good offices of the President of Zimbabwe, in order to "discuss the boundary between Botswana and Namibia around Sedudu/ Kasikili Island" (emphasis added). After touring the Chobe River and viewing Kasikili/Sedudu Island, the three Presidents examined various documents, in particular the 1890 Anglo-German Treaty, which defined the German sphere of influence as being bounded by "the centre of the main channel of [the Chobe] river" (1890 Treaty, Art. Ill (2)). The three Presidents "decided that the issue should be resolved peacefully" (emphasis added) and

"[t]o this end they agreed that the boundary . . . should be a subject of investigation by a joint team of six . . . technical experts ... to determine where the boundary lies in the terms of the [1890] Treaty . . . The Presidents agreed that the findings of [the] team . . . shall be final and binding on Botswana and Namibia" (emphasis added) (Memorial of Namibia, IV, Ann. 10, p. 71; Memorial of Botswana, III, Ann. 55, p. 412).

There was no disagreement between Botswana and Namibia that they should rely on the 1890 Treaty, which determined the line of separation of the sphere of influence between Germany and Great Britain as the centre of the "main channel" of the Chobe River. It would thus seem that their intention was not to settle an existing dispute, if one existed at all, but rather to determine the hitherto uncertain boundary with the assistance of the technical experts who would be able to identify the "main channel" of the Chobe River.

14. The Presidents of Botswana and Namibia were in agreement that [p1123] the boundary should be determined as the "main channel" of the Chobe River as provided for in the 1890 Anglo-German Treaty. It would appear that, in their view, the issue of the legal status of Kasikili/Sedudu Island would not be taken up as such. The territoriality of the Island did not, of itself, constitute an issue.

It should also be noted that the expression "dispute" was not used in the joint Communique issued by the three Presidents. It can be said that, up to and including the time of the meeting of the three Presidents, neither Namibia nor Botswana considered that there had been a dispute. The two States wanted to have the Court determine the actual course of the boundary in terms of the "main channel" as stated in the 1890 Treaty, with the assistance of the joint team of technical experts, who, by their investigations, would determine which — either the northern or the southern channel — was the "main channel". The territoriality of Kasikili/ Sedudu Island would have been automatically settled by drawing such a delimitation line.

*

15. It would seem that, a few months after the meeting at Kasane, the understanding reached by the Presidents of Botswana and Namibia was completely rejected at governmental level. The issue was termed a dispute at the meeting at Windhoek starting on 8 December 1992 (Memorial of Botswana, III, Ann. 56, p. 416), which had been convened in order to decide the terms of reference of the Joint Team of Technical Experts on Boundary (hereinafter "JTTE") that was to be established. The "Memorandum of Understanding" between Botswana and Namibia was drafted on 23 December 1992 (Memorial of Namibia, IV, Ann. 11, p. 73; Memorial of Botswana, III, Ann. 57, p. 428) following this preliminary meeting.

The "Memorandum of Understanding" states in its Preamble that a dispute exists relative to the boundary between Botswana and Namibia, and also refers to the desire of both countries to "settlfe] such dispute by peaceful means in accordance with the principles of both the Charter of the United Nations and the Charter of the Organisation of African Unity" (emphasis added). The "Memorandum of Understanding" sets up a JTTE, consisting of three technical experts from each country "to determine the boundary between Botswana and Namibia around Kasikili/ Sedudu Island in accordance with the [1890] Anglo-German Treaty" (emphasis added); in other words to find whether the northern or the southern channel should be regarded as the "main channel".

The form of words "a dispute exists relative to the boundary between . . . Botswana and . . . Namibia" (emphasis added) first appeared in this "Memorandum of Understanding" of 23 December 1992 and was later employed in the compromis of 29 May 1996 by which the present case [p1124] was brought to the Court. The function of the JTTE should have been limited to the technical recognition of what constitutes the "main channel" of the Chobe River under the terms of the 1890 Anglo-German Treaty. However, this was not the case. The "rules governing the proceedings" in the "Memorandum of Understanding" of 23 December 1992 state that "the Team shall be guided by the general principles of international law regarding the peaceful settlement of international disputes and any relevant international law principles for the delimitation of river boundaries" (Memorandum of Understanding, Art. 8, emphasis added).

I would emphasize that this concept does not accord with what the Presidents of the two States would appear to have had in mind a few months beforehand; indeed it differs greatly.

*

16. On 20 August 1994, after six rounds of meetings, the JTTE completed its work, producing its Final Report, which states that "it emerged that the Joint Team was unable to agree on issues of substance" (Memorial of Botswana, III, Ann. 58, p. 440; Memorial of Namibia, V, Ann. 113, p. 88). The Final Report goes on to state that "[the JTTE] was unable to make a finding determining the boundary between Botswana and Namibia in the area of Kasikili/Sedudu Island in accordance with the provisions of the Memorandum of Understanding." Thus, the JTTE was unable to determine the boundary in accordance with the terms used in the 1890 Anglo-German Treaty.

It would appear that the failure of the JTTE was due to the fact that they did not conduct their work using the mandate, originally agreed at K.asane in May 1992 by the Presidents of Botswana and Namibia, to define where the "main channel" of the Chobe River lay in the eyes of the technical experts.

17. Although the JTTE failed to determine the boundary, it did, however, make a recommendation:

"[T]he Joint Team would recommend recourse to the peaceful settlement of the dispute on the basis of the applicable rules and principles of international law." (Emphasis added.)

This represents a crucial change, in that the JTTE recommends that the "dispute" should be settled on the basis of the "applicable rules and principles of international law" and not by a technical interpretation of the "main channel of the river" as stated in the 1890 Treaty.

I very much doubt that the power to make this recommendation fell strictly within the JTTE's original mandate. It must be recognized that the JTTE did not remain simply a group of technical experts, dealing [p1125]with technical matters concerning the determination of the "main chan-nel", but turned into a body for diplomatic negotiation between the two States. In fact, the six members of the JTTE were not necessarily even technical experts, and the team from Botswana was led by an eminent professor of international law. This clearly demonstrates that the JTTE's purpose changed from the technical or scientific matter of determining the "main channel" of the Chobe River to discussing the more general legal dispute on territorial issues.

Upon receipt of the JTTE's final report and recommendation, the Presidents of Botswana and Namibia, together with the President of Zimbabwe, decided at the Summit Meeting held at Harare on 15 February 1995, after deliberating on the JTTE's report, that "the matter should be referred to the International Court of Justice" for determination (Memorial of Botswana, III, Ann. 59, p. 463, emphasis added).

The compromis, as fully quoted in paragraph 2 of the Judgment, was then, one year later, concluded by Botswana and Namibia on 15 February 1996.

(3) Further Comments on the Lack of Clarity in the Compromis

18. Having examined the process which led up to the conclusion of the compromis, it seems to me quite clear that the position of both countries towards the whole issue was in essence changed somewhat. The original issue, in which neither State gave much weight to the legal status of Kasikili/Sedudu Island, but rather considered that the legal status of the Island would be dependent upon the determination of the boundary, became an issue of the legal status of Kasikili/Sedudu Island.

19. While it was agreed that the boundary should be determined as the centre of the "main channel" of the Chobe River, which separated the spheres of influence under the terms of the 1890 Anglo-German Treaty, no agreement could be reached as to which channel — north or south — constituted the "main channel", a factor which could prove decisive in determining which territory Kasikili/Sedudu Island would fall into.

The issue between the two States could be solved by a scientific investigation or survey concerning the "main channel" of the Chobe River. However, the issue, originally considered to be simply a question of drawing a boundary between the two States, in either the northern chan-nel or the southern channel of the Chobe River (whichever was deemed to be the main channel), has now explicitly been turned into a territorial issue involving sovereignty over Kasikili/Sedudu Island — a change [p1126] which occurred in 1995 at the stage of preparation of the JTTE's Report.

As already mentioned in paragraph 9 above, the second paragraph of the Preamble to the compromis refers only to a "dispute . . . relative to the boundary" (emphasis added), but Article I asks the Court to determine not only the boundary in the Chobe River but also "the legal status of [Kasikili/Sedudu] island" (emphasis added). The 1890 Anglo-German Treaty and the "rules and principles of international law" (and once more I point out that this, according to the compromis, is equivalent to "the general principles of law [as] recognized by civilized nations") being used as the basis for the settlement of the dispute are from the outset mutually contradictory. How can the Court deal with such a contradiction in this case?

It is my belief that the compromis prepared by both States was not drafted in a proper manner.

20. I return to the original question, namely, (i) whether the Court is requested to determine a boundary, on the basis of the 1890 Anglo-German Treaty, which provides for the "main channel" of the Chobe River as a boundary or (ii) whether the Court is to give a final verdict on the territorial issue of Kasikili/Sedudu Island in accordance with the "rules and principles of international law", interpreted as "general principles of law recognized by civilized nations". The real intention of the Parties and the manner in which they have brought this "case" to the Court is unclear. These points have not been clarified by either State in their written documents or during the oral pleadings and the Court's present Judgment also does not address these points.

If option (i) is chosen, the Court will be confined to determining the "main channel" of the Chobe River in either the northern channel or the southern channel as the boundary between the two States. If option (ii) is chosen, the Court must interpret the "rules and principles of international law" relating to territorial sovereignty as applied to Kasikili/ Sedudu Island. This confusion of the issues brought jointly by Botswana and Namibia to the Court puts the latter in an extremely difficult situation in the handling of this "case"; in particular, because the "case" is not based on a unilateral application but submitted by the agreement of both Parties.

21. In this jointly submitted case, the substance of the dispute and the basis on which the Court is asked to rule seem to me to be extremely unclear. In my view, the Court should have asked the Parties to clarify their positions. I wonder if it would not have been possible for the Court to have handed this jointly submitted case back to the Parties with the request that they clarify their common intention and original understanding in coming to the Court, and that they state whether they wish to have the boundary determined or whether they would prefer to treat the deter-mination of the legal status of Kasikili/Sedudu Island as a separate issue and not simply as a result of the determination of the boundary. [p1127]

III. "On the Basis of the 1890 Anglo-German Treaty"

(I) Introduction

22. As I have already stated in paragraph 3 above, this is a case brought by means of a compromis, by which the Parties seek to have the Court determine the boundary and the legal status of the Island on the basis of the criteria which the Parties jointly wish to rely on. The original intention of the Parties was to rely on the 1890 Anglo-German Treaty to assist in the drawing of a boundary along the Chobe River in the area of Kasikili/Sedudu Island. I shall now proceed to an analysis of the 1890 Anglo-German Treaty.

(2) The Significance of the 1890 Anglo-German Treaty

23. There is no difference of views between Botswana and Namibia with respect to the fact that the 1890 Treaty should be regarded as constituting a basic document to determine the boundary between these two States. Let me begin with an examination of that Treaty.

24. Germany, which had had little interest in Africa before the latter part of the nineteenth century, emerged as a colonial State under the leadership of Bismarck and joined other European nations in the partition of Africa. In order to settle the issues relating to Africa, including the determination of the legal doctrine of occupation, the Berlin Conference was convened at the initiative of Bismarck. The General Act of the Conference of Berlin was adopted in 1885 (Memorial of Botswana, II, Ann. 1, p. 1).

In 1884 Germany put South-West Africa under its protectorate and in 1885 Great Britain, by Proclamation of the High Commissioner for South Africa, declared Bechuanaland a British Protectorate (Memorial of Botswana, II, Ann. 3, p. 24). In 1889 negotiations took place between Great Britain and Germany, in which Germany wished to be secured free access from Lake Ngami to the upper waters of the Zambezi River as a part of its sphere of influence (Memorial of Botswana, II, Ann. 4, p. 27; Ann. 5, p. 29).

25. The Anglo-German Treaty of 1 July 1890 determined the separation of the spheres of influence of the two States. The Treaty reads in part:

"The undersigned
………………………………………………………………………………………………
Have, after discussion of various questions affecting the Colonial interests of Germany and Great Britain, come to the following Agreement on behalf of their respective Governments :
………………………………………………………………………………………………
In South-West Africa the sphere in which the exercise of influence is reserved to Germany is bounded:
………………………………………………………………………………………………

[p1128]
2. To the east by a line . . . [which] runs eastward along [the 22nd parallel of south latitude] to the point of its intersection by the 21st degree of east longitude; thence it follows that degree northward to the point of its intersection by the 18th parallel of south latitude; it runs eastward along that parallel till it reaches the River Chobe; and descends the centre of the main channel of that river to its junction with the Zambesi, where it terminates.
………………………………………………………………………………………………………
The course of the above boundary is traced in general accordance with a Map officially prepared for the British Government in 1889." (Anglo-German Treaty, Art. Ill, para. 2.) (Memorial of Botswana, II, Ann. 11, p. 185; Memorial of Namibia, IV, Ann. 4, p. 6.)

*
26. The 1890 Treaty is an instrument which determined the respective spheres of influence of the Parties in this region of Africa but which certainly did not fix national boundaries there between the territories of Germany and Great Britain. The limit of the German sphere of influence was fixed as the "centre of the main channel of the Chobe River", but in that Treaty no concrete boundary line was indicated in this geographically complex area. The determination of the boundary, which would certainly have had the effect of determining the legal status of Kasikili/Sedudu Island, was at that time a matter far removed from the actual purpose of the Treaty.

27. The 1889 map that purports to illustrate Article III of the 1890 Anglo-German Treaty (Memorial of Botswana, Appendix II, Map 3) is, in my view, too reduced in scale to be of great assistance. The course of the Chobe River on this map is taken directly from the map prepared in 1881 by Dr. B. F. Bradshaw for the Royal Geographical Society. The Bradshaw map indicates certain geographical features of the area and shows the northern and southern channels of the Chobe River but, naturally, did not define any boundary (Memorial of Namibia, V, Ann. 102, p. 35; Memorial of Namibia, VI, Atlas 1/2) (Memorial of Botswana, Appendix II, Map 1) and has no significance for the determination of the boundary in this area.

(3) The Meaning of "Main Channel" in the 1890 Treaty

28. A great many explanations have been given by both Parties concerning the phrase "the centre of the main channel of [the Chobe River]" in Article III of the 1890 Anglo-German Treaty. In particular, both Parties have devoted a great deal of attention, especially during the oral hearings, to the purported difference between this concept and that used [p1129] in the other authentic text, the German one, which reads: "Thalweg des Hauptlaufes dieses Flusses".

The concept expressed by the German language text and that expressed by the English language text may not be identical. The English word "centre" is simply an expression used in geometry while the German word "Thalweg" has some legal connotation. The fixing of the "centre" of the main channel of the river is a matter to be determined by a geographer or a surveyor. In my view, however, the German delegation at the negotiation of the 1890 Treaty does not seem to have used the German expression "Thalweg" in order to give a meaning different from the English expression "centre" or in order to give the word a legal sense.

As stated in the Judgment (para. 46), the original provision of this part of the 1890 Treaty, initialled by Lord Salisbury and by Count Hatzfeldt, and transmitted to the British Foreign Office as "Draft Articles of Agreement" read:

"[The boundary] runs eastward . . . till it reaches the River Chobe, and descends the centre of that river to its junction with the Zambesi, where it terminates." (Memorial of Namibia, IV, Ann. 26, p. 121, emphasis added.)

Afterwards the British side proposed the insertion of the words "the main channel of so that the sentence read "the centre of the main channel of that river". That proposal was accepted by the German side and translated first as "in der Thal-Linie des Hauptlaufes dieses Flusses" and, in the end, the word "Thal-Linie" was replaced with the word "Thalweg". I would like to point out that the Judgment clearly, and in my view quite properly, states that "[t]he German text is therefore a word-for-word translation of the British proposal and follows the English text" (Judgment, para. 46).

29. At all events, the German words "Thalweg des Hauptlaufes" have the same meaning as the English words "centre of the main channel". The different interpretation of the German words that was given at the oral pleadings does not convince me and I fail to understand why the Parties have given so much weight in their respective pleadings to a discussion of the word "Thalweg" and why the Court, in a similar way, shows so much concern with the use of and definition of this particular word so extensively in so many parts of its Judgment (Judgment, paras. 21-27, 46, and 89). The word "Thalweg" appears more than 20 times in the Judgment. I reiterate, the German expression is simply a translation of the English original text. The "centre of the main channel" is the original expression and reflects the idea of the negotiators of the 1890 Anglo-German Treaty. In the latter part of the Judgment, the expression "Thalweg" is replaced by "line of deepest soundings" — which follows the suggestions of the Parties during the oral hearing — and this concept appears in subparagraph (1) of the Judgment's operative part. I think that the Court should have said in its operative part simply that the [p1130]boundary between Botswana and Namibia "follows the centre of the northern channel" rather than "follows the line of deepest soundings in the northern channel".

*

30. It is clear to me that there was nothing in the minds of the officials who negotiated the 1890 Treaty that could indicate that they had decided that the separation line between their respective spheres of influence should be anything other than the centre of the "main channel" of the Chobe River. The concept of "channel" is a strictly scientific issue. However, what constitutes "the main" channel is subject to a degree to interpretation. The concept of the "main channel" may well be defined by various criteria such as the breadth of the river, the depth of the water, the volume of waterflow, bed profile configuration, and so forth, as suggested in certain scientific works of reference (Judgment, paras. 29 and 30). The Judgment properly states that there is "[not] one single criterion in order to identify the main channel of the Chobe" (para. 30).

31. I submit that the fact that the original English text, namely the term "centre of the river", was replaced by the term "centre of the main channel of the river" and, in the German text, the word "Thalweg" was used to mean the "centre" of the main channel, might be interpreted as reflecting an interest on the part of the parties to the 1890 Treaty, in their choice of the Chobe River as the boundary, in the navigation potential of that River, thus gaining access to the Zambezi River. It should, however, be noted that it was not known at that time whether navigation through the Chobe River was feasible. It was merely of potential interest to each side. This is properly noted in the Judgment (paras. 40 and 44). Since there existed no immediate interest in navigating the Chobe River, and given that the hydrological condition of the river was unknown, the parties to the 1890 Treaty — without thereby seeking to delimit the boundary — employed the phrase "centre of the main channel" with a view to the navigability of the river, but in purely theoretical terms.

Subject to some minor exceptions, the Chobe River has to date not been navigated for transportation purposes. If the "main channel" should be considered in terms of navigability, then the Court would have difficulty in choosing between the northern and the southern channel as a boundary, since neither of those two channels has in the past or at the present time satisfied the conditions of navigability in a substantive or commercial sense.

32. If, however, the Court is to decide the boundary in terms of the "main channel" of the river, in whatever manner the words in the 1890 Treaty might have been interpreted at that time, then it can proceed to find the whereabouts of the main channel in the general sense. For this purpose the Court needs the assistance of a hydrological expert and [p1131] should have sought the help of a specialist in this subject, either as a witness or as an expert to be called by the Court, who could, first, inform the Court what criteria were most suitable for the definition of the main channel in this particular geographical situation and, second, which of the two channels would in reality meet those criteria.
Instead the Court has, in one way or another, dealt with the views expressed by scientists or specialist members of the opposing teams of the Parties. The views of these scientists or specialists are at times contradictory. The Court has, in fact, determined the northern channel as the "main channel" without the benefit of an expert opinion obtained from an independent person. It has relied upon its own interpretation of the geographical and scientific criteria, and has come to its own conclusion that " in accordance with the ordinary meaning of the terms that appear in the pertinent provision of the 1890 Treaty, the northern channel of the River Chobe around Kasikili/Sedudu Island must be regarded as its main channel" (Judgment, para. 41). Although, in my view, the Court has not dealt correctly with this matter, which involves scientific, hydrographic, potamological or topographical issues, I am, however, not in a position to state that the Court's decision is incorrect.
.
(4) How Has the "Main Channel" been Recognized on Various Occasions in the Past?

33. In order to determine at present the boundary between Botswana and Namibia it is extremely important to ascertain how this main channel of the Chobe River, as referred to in Article III (2) of the 1890 Treaty, has been recognized in the past. I will devote a separate part of this opinion to a discussion of this matter. These past practices are extensively referred to in the Judgment but from a totally different aspect.

IV. "On the Basis of the Rules and Principles of International Law"

34. The Court is requested to make a determination "on the basis of not only the 1890 Treaty but also "the rules and principles of international law" {compromis, Art. I). As I stated above, these words are interpreted in the compromis as meaning the "general principles of law recognized by civilized nations", as provided in Article III of the compromis. It may be noted that this interpretation, stated in Article III of the compromis, was quite new and was not mentioned in the work of the JTTE which constituted the basis of the compromis. I have to ask myself whether the Parties to the compromis really intended to limit the interpretation of the wording in Article I to the meaning stated in Article III. [p1132]

35. If, as the compromis suggests, one takes the words "the rules and principles of international law" to mean the "general principles of law recognized by civilized nations", then the argument as to whether "prescriptive title" was acquired, on whatever basis, in connection with the legal status of Kasikili/Sedudu Island, would be relevant. The Court is quite justified in taking up the issue of the doctrine of prescription in this regard (Judgment, paras. 94-99). The Court concludes, however, that cultivation by the Masubia people or the occasional exercise of authority in one way or another over the Island would not have constituted a basis for acquisitive prescription and reaches a negative conclusion on this point (Judgment, para. 99). I fully agree with the Court's conclusion on this point.

36. What other "general principles of law recognized by civilized nations" could then have been suggested as a basis for the Court's determination of the matter? I see no reference in the arguments of the Parties to this element. I find no reason to take "the rules and principles of inter-national law" as a basis for the Court's determination, as distinct from the 1890 Anglo-German Treaty.
V. How the "Main Channel" of the Chobe River Was Recognized in Past Practice and How That Would Assist the Court to Determine the Boundary along the Chobe River

(I) Introduction

37. As I have stated in paragraph 33 above, it is necessary to examine how the boundary of the Chobe River and the status of Kasikili/Sedudu Island have been viewed at varying times in the past by the respective authorities in the area in the maps, in certain relevant documents or even in certain practices.

These documents and practices are referred to extensively in the Judgment, but rather from the standpoint of whether they constitute "any agreement relating to the treaty which was made between all the parties in connexion with the conclusion of the treaty" and/or "any instrument which was made by one or more parties in connexion with the conclusion of the treaty and accepted by the other parties as an instrument related to the treaty" as provided for in the Vienna Convention on the Law of Treaties (Art. 31, para. 2 (a),(b)), for purposes of interpretation of the 1890 Anglo-German Treaty (Judgment, paras. 47-70, 75 and 78). The Judgment makes many references to the Vienna Convention and concludes generally that the practices to which it refers extensively, and which I quote later in this section, constitute neither "subsequent agreement" nor "subsequent practice" in terms of that Convention (Judgment, para. 79).

38. On this point, I am afraid that I cannot share the view taken in the Judgment that these practices, maps and documents are relevant purely for the purpose of interpretation of the 1890 Treaty. In my view, the rele-[p1133]vant facts and activities may usefully be considered by the Court as an aid to determining the boundary of the Chobe River and the legal status of the Island, but not for the purpose of the Court's interpretation (with regard to the Vienna Convention on the Law of Treaties) of the 1890 Treaty. In my view, these past practices themselves constitute a decisive factor enabling the Court to determine the boundary between Botswana and Namibia along the northern channel of the Chobe River.

In the part of my opinion that follows, I refer to several incidents and quote from the early documents. Those references are, to a great extent, the same as those cited in the Judgment but I include them nevertheless as, from my standpoint, they are of great importance.

(2) Treatment of Maps

39. I should like to add a few words on the significance in this particular case of a number of maps of the region produced since 1890 and presented to the Court by the Parties. I count as many as 52. I have grave doubts as to whether the existence of so many maps in this case will be of help in finding a solution to this matter. Some of the maps indicate the width of the northern channel and of the southern channel around Kasikili/Sedudu Island, and are thus useful in providing some geographical details of the region. However, some of the cartographers have gone so far as to indicate on their maps a "boundary", which could be interpreted as being a political boundary between the northern and southern banks of the Chobe River.

40. The Judgment develops the view of the Court regarding the various maps of this area submitted to it and the Court properly considers that it is "itself unable to draw conclusions from the map evidence produced in this case" (Judgment, para. 87). I share the Court's view in this regard. I should, however, like to make some general comments on these maps, as follows.

First, some maps were simply reproduced from a previous edition without any additional survey having taken place.

Secondly, the Chobe River region had, before 1890, been explored by certain individuals, amongst them Selous and Livingstone, but obviously the maps they produced did not show any political boundary. A map produced by a relevant government body may sometimes indicate the government's position concerning the territoriality or sovereignty of a particular area or island. However, that fact alone is not determinative of the legal status of the area or island in question. The boundary line on such maps may be interpreted as representing the maximum claim of the country concerned, but does not necessarily justify that claim.

Thirdly, a claim to territory can only be made with the clear indication [p1134] of a government's intention, which may be reflected in maps. A map on its own, with no other supporting evidence, cannot justify a political claim. In this particular case, despite the existence of so many maps and despite the considerable discussion by both Parties on the subject of their interpretation, in the final analysis, all of this is in my view utterly irrelevant.

41. To my mind, the drawing of a political boundary is not a task for a cartographer unless he has been given a clear indication of its placement. No great weight should be given to any boundary depicted by such maps.

The Parties included in their oral presentation a list indicating which, of the large number of maps, placed the boundary either to the north or to the south. This, in my view, was at best an exercise in futility and at worst absurd.

(3) The Geographical Conditions of the Area Surrounding KasikililSedudu Island and the Political and Social Situation of the Island up to the Middle of This Century

42. This area was essentially unknown before the conclusion in 1890 of the Anglo-German Treaty, except for the report of Livingstone's expedition, "Missionary Travels and Researches in South Africa" (Memorial of Namibia, V, Ann. 129, p. 197; Memorial of Namibia, I, p. 23), the report of the explorer Selous in 1874 (referred to, but not fully quoted, in Memorial of Namibia, V, Ann. 138, p. 229), and the Schulz-Hammar report of 1884, "The New Africa — A Journey up the Chobe and down the Okovanga Rivers" (referred to, but not fully quoted, in Memorial of Namibia, V, Ann. 137, p. 227). As far as I can tell, none of these reports refers to the existence of an island now known as Kasikili/Sedudu Island.

43. Whether at that time Kasikili/Sedudu Island was submerged during the rainy season or whether there was any continuous flow of water throughout the year is not known. Some explanation has been given by the scientists engaged by the Parties to this case but their explanations differed, nor was it altogether clear whether they were talking about the situation a hundred years ago or at the present time. At any rate, the facts they presented were not explained to the Court by a witness or by an expert who had made the required solemn declaration. The fact appears to be that there existed no reliable topographical description of this area at that time. It is extremely difficult to ascertain from any existing available information the geographical situation of this region, namely, Kasikili/Sedudu Island and the surrounding area of the Chobe River. [p1135]

44. It appears to me that, in the oral and written pleadings in this case, the Parties have, in the main, concentrated on the interpretation of the terms contained in the 1890 Treaty (such as the "centre of the main channel of the river") but have not greatly discussed the political and social status or situation of the north and south banks of the Chobe River.

45. Germany, which in 1884 placed South West Africa under its Protectorate, was greatly concerned about access from the direction of the Ngami Lake to the east towards the Zambezi River and had not even the slightest interest in exercising control over a small island in the Chobe River. Great Britain, on the other hand, had in 1885 placed Bechuana-land under its Protectorate and put the region under the control of the Governor of British Bechuanaland.

Germany made no territorial claim, not even over the Eastern Caprivi Strip to the north of the Chobe River, and the first presence of a German administration in this region was in 1909 after the establishment of the office of the German Governor in South West Africa in 1908 at Wind-hoek. The de facto authority of Great Britain existed in Caprivi until 1914. It is assumed that, at that time, Great Britain's control of the region extended northwards beyond the Chobe River.

46. During the First World War, Eastern Caprivi, which had been under German administration, was occupied by the British Army mobilized from South Rhodesia and was placed under the authority of the District Commissioner of the Bechuanaland Protectorate in Kasane (Memorial of Namibia, I, p. 93). In 1919, after the First World War, the Union of South Africa became the administering power for the whole of present-day Namibia under the mandate of the League of Nations — which means, if I may say so, that the Union of South Africa was under British influence, albeit indirectly. In the period 1915-1929 Caprivi was administered by the Bechuanaland administration on behalf of the Government of the Union of South Africa. No objection was raised to the cultivation of Kasikili/Sedudu Island by Caprivi tribesmen.

The difference in status between the area to the north and the area to the south of the Chobe River did not actually cause any practical difficulties in this post-war period; these arose only after the Second World War. It is reported that the British Police patrolled both the northern and southern banks as peace officers.

47. A report (the Eason Report) produced by Captain Eason of the police of the Bechuanaland Protectorate (Great Britain) on 5 August 1912, entitled "Report on the main channel of the Linyanti (or Chobe) river" (frequently cited in the Judgment, in paras. 33, 42, and 52-55), gives some geographical description of the area (Memorial of Namibia, IV, Ann. 47, p. 173; Memorial of Botswana, III, Ann. 15, p. 225). This Report states that "[h]ere [Captain Eason] considers] that undoubtedly the North should be claimed as the main channel" (emphasis added) and, in the sketch-map attached to this report, the northern channel [p1136] was, from a geographical point of view, taken as being the main channel.

Since that 1912 report, there seems to have been no reliable report of this region until the Trollope-Redman report prepared in the mid-1940s, to which I will refer later.

(4) The Confrontation in the 1940s between the Authorities of the Union of South Africa and the British High Commissioner's Office for the Bechuanaland Protectorate

48. After the Second World War, despite the termination of the mandatory system of the League of Nations, the Union of South Africa did not acquiesce in transforming this mandatory area to the new system of Trusteeship under the United Nations. Thus, the separation or friction between the regimes controlling the territories of the Union of South Africa (which became a Republic and left the Commonwealth in 1961) and the British Protectorate of Bechuanaland became apparent. It is only since that time that the question of the boundary between the two entities mentioned above, including the status of Kasikili/Sedudu Island, emerged.

49. In 1940 Major L. Trollope, the Magistrate for the Eastern Caprivi Zipfel (hereinafter "Strip") (to the north of the Chobe River), surveyed this area with the co-operation of the Bechuanaland Protectorate police in Kasane (to the south of the Chobe River) and submitted his report on the administration of the Eastern Caprivi Strip to the Secretary for Native Affairs in Pretoria (Memorial of Namibia, IV, Ann. 58, p. 229). No mention was made of Kasikili/Sedudu Island in that report.

50. Nearly ten years later, in 1948, an exchange of letters took place between the Office of the Magistrate in Windhoek, Caprivi Strip (to the north of the Chobe River), and the British Authorities in Kasane (to the south of the Chobe River), concerning the international status of this region, including Kasikili/Sedudu Island. Major Trollope (Magistrate for the Eastern Caprivi Strip) addressed a letter on 3 January 1948 to Mr. V. Dickinson (District Commissioner in Maun, Bechuanaland), entitled "Channel between Kasikili Island and Kabuta and Kasika Villages", referring to the application by a Mr. Ker for permission to transport timber through the northern channel (Memorial of Namibia, IV, Ann. 59, p. 262) (see Judgment, paras. 40 and 56).

51. A few weeks later, a report dated 19 January 1948 was jointly prepared by Major Trollope and Mr. N. V. Redman ([Assistant] District Commissioner at Kasane, Bechuanaland Protectorate), entitled "Joint Report on the boundary between the Bechuanaland Protectorate and the [p1137] Eastern Caprivi Zipfel: Kasikili Island" (see Judgment, paras. 42 and 57-60) in which it was stated that:

"3. We find after Separate examination of the terrain and the examination of an aerial photograph that the 'main Channel' does not allow the waterway which is usually shown on maps [the southern channel] as the boundary between the two Territories.

4. We express the opinion that the 'main Channel' lies in the waterway /the northern channel] which would include the island in question in the Bechuanaland Protectorate.

5. On the other hand we are satisfied, after enquiry that since at least 1907, use has been made of the Island by Eastern Caprivi Zipfel tribesmen and that that position still continues.

6. We know of no evidence of the Island having been made use of, or claimed, by Bechuanaland Tribesmen or Authorities or of any objection to the use thereof by Caprivi Tribesmen being made." (Memorial of Namibia, IV, Ann. 60, p. 264.)

*

52. Major Trollope, in his letter of 21 January 1948 addressed to the Secretary of Native Affairs in Pretoria entitled "Bechuanaland-Eastern Caprivi Zipfel Boundary" (see Judgment, para. 58), seems to have conceded, in paragraph 3, that the boundary should be in the northern channel but that the people of Eastern Caprivi should continue to be allowed to cultivate the Island. The letter stated:

"There is no doubt if the wording of the 1890 Treaty is applied to the geographical facts as they exist today that the true inter-territorial boundary would be the northern waterway and would include Kasikili Island in the Protectorate." (Memorial of Namibia, IV, Ann. 61, p. 271, emphasis added.)

53. It is known that, in spite of the suggestion by Major Trollope regarding the northern channel, the Union of South Africa was reluctant to admit that the northern channel was the main channel of the Chobe River; see the letter of 12 June 1948 from the Secretary of Justice of the Union of South Africa to the Secretary for External Affairs in Pretoria entitled "Bechuanaland — Eastern Caprivi Zipfel Boundary":

"The main channel is north of Kasikili Island whereas it is apparently usually shown on maps as being south of the island. The map referred to in the [1890] Treaty is not available to us, but assuming that on that map also the main channel is shown as being south of the island, the question arises whether there was not, before the con-[p1138]elusion of the Treaty, a shifting of the main channel from the southern waterway to the northern." (Memorial of Namibia, IV, Ann. 62, p. 277, emphasis added.)

*

54. In a letter dated 14 October 1948 from the Secretary to the Prime Minister and for External Affairs of the Union of South Africa (responsible for the area north of the Chobe River), to the Administrative Secretary to the British High Commissioner for Basutoland, the Bechuana-land Protectorate and Swaziland (responsible for the area south of the Chobe River), it is stated that, as far as the former remembered, the boundary had never been changed from the southern channel to the northern channel. It seems that the issues between the two authorities at that time were concerned with the transport of timber through the northern channel of the Chobe River and the cultivation of Kasikili/ Sedudu Island by Caprivi tribesmen. While the Union of South Africa was aware of the application for permission to transport timber by a firm in Bechuanaland, its main concern was the continuation of the cultivation of the Island by the tribesmen of the Eastern Caprivi Strip. This is shown by the following quotation from the letter:

"It is understood that the necessity for consideration of the matter arises from the fact that a certain river transport venture, which proposes to transport timber down the river from a sawmill in Bechuanaland has raised the question of the correct boundary both in representations to the Magistrate, Eastern Caprivi Zipfel and to the Bechuanaland authorities.

The Report discloses that while the main channel of the Chobe River is shown on maps as passing to the South of Kasikili Island it in fact passes to the North of that Island.

It has been confirmed, as a result of exhaustive enquiries, that there has been no shifting of the main channel of the river from South to North within living memory. The facts, therefore, point to the maps being incorrect.

As against the foregoing there is evidence that the Island has been cultivated by Caprivi Tribesmen since at least 1907 and that their right to the occupation of the Island has at no time been disputed.

The Union Government is anxious to preserve the rights of the Caprivi Zipfel tribesmen on the Island and it is understood that the Bechuanaland authorities desire the use of the Northern channel for navigation purposes. As there would appear to be no conflict of interests it should be possible to come to an arrangement which is mutually satisfactory." (Memorial of Namibia, IV, Ann. 63, p. 280.)

The letter of 4 November 1948 of the Administrative Secretary to the [p1139] British High Commissioner addressed to the Secretary of State for External Affairs in the Union of South Africa states that:

"I am directed by the High Commissioner for Basutoland, the Bechuanaland Protectorate and Swaziland to inform you that the Resident Commissioner of the Bechuanaland Protectorate has directed the Assistant District Commissioner, Kasane, that tribesmen of the Caprivi Zipfel should be allowed to cultivate land on Kasikili Island, if they wish to do so, under an annual renewable permit." (Memorial of Namibia, IV, Ann. 64, p. 281.)

The letter of 14 February 1949 from the Secretary to the Prime Minister and for External Affairs to the Chief Secretary to the British High Commissioner on Basutoland, the Bechuanaland Protectorate and Swaziland, sounded out the possibility of agreeing that the Island should belong to the northern bank (South West Africa) but that the navigation route should remain as the northern channel:

"From the available information it is clear that Caprivi Tribesmen have made use of the Island for a considerable number of years and that their right to do so has at no time been disputed either by Bechuanaland Tribesmen or the Bechuanaland authorities.

It was further understood that the interests of the Bechuanaland authorities centred in the use of the Northern Channel of the Chobe for navigation purposes.

My object in writing to you was therefore to ascertain whether agreement could not be reached on the basis of your Administration recognising the Union's claim to Kasikile Island subject to it issuing a general permit for the use of the Northern waterway for navigation purposes." (Memorial of Namibia, IV, Ann. 65, p. 283.)

55. In a letter of 6 June 1949 addressed to Lord Noel-Baker (Secretary of State for Commonwealth Relations), the British High Commissioner seems to have been ready to accept the proposal of the Union of South Africa that the southern channel would constitute the boundary, as shown by the following quotation:

"2. Part of that boundary is formed by the main channel of the Chobe or Linyati River which runs eastwards into the Zambesi, and divides the northern border of the Bechuanaland Protectorate from a narrow strip of territory known as the Caprivi Zipfel. About 10 miles west of its junction with the Zambesi, the Chobe river encloses Kasikile Island, a small strip of land about IV2 square miles in area; this has hitherto been regarded as part of the Caprivi Zipfel, since maps show that the main channel passes to the south of the island.

3. The question of the correct boundary was raised by a firm which intends to transport timber down the river, and the Union Government, having examined the question, find that the main [p1140]channel is to the north of the island, and that there has been no change in the course of the channel within living memory. I enclose a copy of a note provided by the Union Government which was jointly recorded on the 19th January, 1948, by the Magistrate of the Eastern Caprivi Zipfel and the District Commissioner of Kasane, Bechuanaland Protectorate, together with a copy of the sketch map mentioned therein.

4. The Resident Commissioner of the Bechuanaland Protectorate considers that the Union proposal to set the boundary in the southern channel need not be resisted, if the use of the northern channel for navigation is guaranteed for the inhabitants and Government of the Bechuanaland Protectorate. This guarantee the Union Government are prepared to give.

5. I consider in the circumstances that the proposal of the Union Government is acceptable, and would be glad to have your approval of it." (Memorial of Namibia, IV, Ann. 66, p. 284.)

*

56. This correspondence as referred to in paragraphs 54 and 55 above, seems to indicate the readiness towards the end of the 1940s of the Bechuanaland Protectorate to concede that the southern channel would constitute the boundary if the transportation of timber could be con-tinued by Mr. Ker through the northern channel. However, that suggestion, addressed to Lord Noel-Baker, did not receive the approval of the British Government.
After the exchange of letters between the Union of South Africa and the Bechuanaland Protectorate, there was no progress at that time on the issue concerning the boundary.

(5) The Occurrence of Incidents in 1984 after Botswana's Independence in 1966, and the Joint Survey Which Followed

57. On 25 October 1984 an incident took place in which a South African patrol boat on the Chobe River was shot at by Botswana Armed Forces (Memorial of Namibia, IV, Ann. 84, p. 329). This can be regarded as the beginning of the territorial dispute between the two entities. At an intergovernmental meeting held in Pretoria on 19 December 1984 (Memorial of Botswana, III, Ann. 50, p. 396) it was decided that a joint survey should be undertaken to determine whether the main channel of the Chobe River was located in the northern or the southern channel (Memo-rial of Botswana, III, Ann. 48, p. 384).

In fact, the July 1985 report on the "Chobe River Boundary Survey: Sidudu/Kasikili Island" suggested in conclusion: "The main channel of the Chobe River now passes Sidudu/Kasikili Island to the west and to the [p1141] north of it" (emphasis added). However no effort was made to find a solution to the political issue, namely, the national boundary between the powers to the north and south of the river.

*

58. The telex dated 22 October 1986 from "Pula Gaborne" Botswana (responsible for the area south of the Chobe River) to "Secextern" Pretoria (responsible for the area north of the Chobe River), referring to the discussion held on 13 October 1986, states:

"It will be recalled that the Botswana side submitted that Sidudu/ Kasikili Island is part of the territory of Botswana, as confirmed by the Botswana/South Africa joint team of experts which reported to the two Governments in July, 1985. Pula wishes to inform Secextern that the Government of Botswana has since occupied Sidudu/Kasikili Island and expects the Government of South Africa to respect the sovereignty and territorial integrity of the Republic of Botswana in respect of the island." (Memorial of Botswana, III, Ann. 52, p. 406.)

The South African authorities suggested that a meeting be convened for the solution of the problem. The exchange of communication ended with a telex from the Botswana authorities dated 25 November 1986, which read as follows:

"The joint Botswana/South Africa team of experts were never asked to demarcate an international boundary but 'to determine whether the main channel of the Chobe River is located to the north or south of Sidudu Island'. The joint team confirmed what had always been the fact, namely that the main channel is located to the north of the island, and that is where the boundary is.

It is therefore clear that adequate clarification of the matter has been made to satisfy normal requirements and no further discussion of the matter is necessary." (Memorial of Botswana, Ann. 54, p. 410; emphasis added.)

(6) What Does the Past Practice Indicate?

59. After an examination of certain incidents that occurred in the area, as well as the correspondence between the authorities of the northern bank and southern bank and certain surveys conducted in the course of the past hundred years, I conclude that the northern channel of the Chobe River had been regarded, implicitly or explicitly, as the boundary separating the authorities on the northern and southern banks, and that Kasikili/Sedudu Island had been regarded as being under the authority of [p1142] the south, despite the occasional use of the Island by tribespeople from the northern side.

The Judgment, however, refers to these same past practices as if they might serve to assist it in interpreting the 1890 Anglo-German Treaty as provided for in the Vienna Convention on the Law of Treaties, and the Court came to the conclusion that those practices were not in fact capable of constituting "subsequent practice" or "subsequent agreement" within the meaning of the Vienna Convention. I would emphasize once more that in my view this case is not one directly related to the application of the provisions of the Vienna Convention on the Law of Treaties to the 1890 Anglo-German Treaty, to which latter Treaty neither Botswana nor Namibia is a party.

I refer above to these past practices, as decisive factors in assisting the Court to determine the course of the boundary in the Chobe River and, hence, to determine the status of Kasikili/Sedudu Island as a part of the territory of Botswana.

VI. Conclusion

60. I suggested at the outset that the compromis agreed by Botswana and Namibia on 15 February 1996 and filed in the Registry of the Court on 29 May 1996 was not clearly drafted, with the result that the Court would not be able properly to ascertain the Parties' real intention in submitting the "case" to it. The first thing the Court must do is to ascertain whether the Parties wish it to determine the boundary between the two States along the Chobe River or the legal status of Kasikili/Sedudu Island. These two issues, rather than being complementary, may well be contradictory. I suggested that the Parties might have been asked to clarify their common position on the subject of the dispute.

61. The parties to the 1890 Treaty did not attempt to delineate the boundary in the area of the Chobe River but wanted, by the use of the words the "main channel" of the river, to separate their respective spheres of influence taking into consideration the potential possibility of naviga-tion along the Chobe River in order to have access to the Zambezi River. In fact, the Chobe River has not been in the past and is not at the present time used in any substantial way for the purpose of navigation. Thus the words the "main channel of the Chobe River" may well today be understood in the ordinary sense in hydrological terms. I regret that the Court made no attempt to obtain the opinion of an expert regarding the main channel of the Chobe River and relied instead on the opinions of experts who were members of the Parties' respective teams. I accept, however, that the Court has determined the northern channel as the boundary in accordance with the ordinary meaning to be given to the relevant terms as it understands them and I have no objection to its findings on the matter. [p1143]

62. I agree with the finding of the Judgment that "the rules and principles of international law", as a basis for determination of the boundary and the legal status of the Island, have no significant role to play in this case.

63. I would rather suggest that the past practices — the geographical surveys and the correspondence between the authorities of the northern and southern bank — which were indicated sufficiently in the Judgment and of which I have also made an extensive analysis, are of themselves the most important and decisive element in assisting the Court to determine that the boundary between Botswana and Namibia is located in the northern channel and that Kasikili/Sedudu Island thus falls within the territory of Botswana.

(Signed) Shigeru ODA. [p1144]


SEPARATE OPINION OF JUDGE KOOIJMANS

Namibia's alternative claim of acquisitive prescription — Admissibility — Reference to "rules and principles of international law" in Special Agreement — Subsequent practice and acquisitive prescription.

Kasane Communiquι — Mutual commitments linked to settlement of dispute
— Waters around Island part of unitary whole irrespective of location of boundary — Use of these waters similar to non-navigational uses — Convention on Law of Non-navigational Uses of International Watercourses — Helsinki Rules— Principle of equitable and reasonable utilization.

1. Although I have voted in favour of the operative provisions of the Judgment, I feel compelled to append some observations since I find myself unable to concur with part of the Court's reasoning. 1 also wish to make a number of additional remarks to supplement the conclusions of the Court concerning the use of the waters around Kasikili/Sedudu Island.

I

2. I agree with the Court's conclusion that the boundary between Botswana and Namibia follows the line of deepest soundings in the northern channel of the Chobe River around Kasikili/Sedudu Island and that this Island forms part of the territory of Botswana.

3. That finding is the result of the Court's interpretation of the Anglo-German Treaty of 1 July 1890 and is in conformity with Article I of the Special Agreement of 15 February 1996, in which the Parties requested the Court to determine, on the basis of the Anglo-German Treaty and the rules and principles of international law, the boundary between them around Kasikili/Sedudu Island and the legal status of the Island.

4. In my opinion the Court's conclusion with regard to the legal status of the Island should, however, not have been based simultaneously upon the consideration that the correctness of Namibia's claim that it has title to Kasikili/Sedudu Island not only on the basis of the 1890 Treaty, but also, in the alternative, on the basis of the doctrine of prescription, has been insufficiently established by Namibia and that this claim, therefore, cannot be accepted (paras. 99 and 101 of the Judgment).

5. I do not disagree with the Court's analysis of this claim nor with its evaluation of the evidence adduced by Namibia to support it; in my opinion, however, this claim should have been declared inadmissible right away. [p1145]

6. In the written and oral proceedings Namibia has claimed that there is an alternative ground — entirely independent of the terms of the 1890 Treaty — by which it is entitled to sovereignty over Kasikili/Sedudu Island, viz., prescription, acquiescence and/or recognition. It contended that the Special Agreement, by referring in its Article 1 to the rules and principles of international law, explicitly or implicitly allowed the Court to apply the doctrine of acquisitive prescription as a separate ground for Namibia's sovereignty over the Island.

7. For its part, counsel for Botswana maintained that it would be "contrary to common sense to presume that the general reference to 'the rules and principles of international law' should prevail over the reference to a specific international agreement which defines the boundary in question' (emphasis in original).

8. The Court is of the view that the reference in the Special Agreement to the "rules and principles of international law" not only authorizes the Court to interpret the 1890 Treaty in the light of those rules and principles but also to apply them independently and that, consequently, the Special Agreement does not preclude the Court from examining arguments relating to prescription (para. 93).

9. With all due respect, I do not find the Court's reasoning persuasive. The fact that Article III of the Special Agreement states that the rules and principles of international law applicable to the dispute shall be those set forth in the provisions of Article 38, paragraph 1, of the Court's Statute can hardly be called enlightening; it only refutes — as the Court correctly states — Botswana's argument that the Special Agreement allows the Court to apply only the rules and principles of international law concerning treaty interpretation.

10. But this reference in Article I, as specified in Article III of the Special Agreement does not add anything to what the Court is not already entitled to do by the Statute. In the case of Continental Shelf (Tunisia!Libyan Arab Jamahiriya) the Court stated:

"While the Court is, of course, bound to have regard to all the legal sources specified in Article 38, paragraph 1, of the Statute of the Court in determining the relevant principles and rules applicable to the delimitation, it is also bound, in accordance with paragraph 1 (a), of that Article, to apply the provisions of the Special Agreement." {I.C.J. Reports 1982, p. 37, para. 23.)

11. In the Special Agreement the Parties ask the Court to determine, on the basis of the 1890 Treaty and the rules and principles of international law — without dissociating the latter from the former — the boundary between Namibia and Botswana around Kasikili/Sedudu Island and the legal status of the Island — again, without dissociating the latter from the former. [p1146]

In my opinion, therefore, the Special Agreement precludes the Court from applying the rules and principles of international law independently of the Treaty. It is the Treaty which determines the boundary. Without interpreting and applying the Treaty the Court is not able to determine the boundary and the legal status of the Island as it is requested to do by the Special Agreement.

12. The Special Agreement asks the Court to do two things: first, to determine the boundary between Namibia and Botswana around Kasikili/ Sedudu Island, and, second, to determine the legal status of the Island. The logical order seems to be to answer the first question first. In order to do so the Court must on the basis of the Anglo-German Treaty determine whether the northern or the southern channel is or contains the main channel. Once that determination has taken place, the second question is implicitly answered as well: if the northern channel is the main channel, the Island belongs to the territory of Botswana; if the southern channel is the main channel, it is part of Namibia; in other words, the Island goes with the boundary.

13. The second question, that of the legal status of the Island, can in my opinion only be answered independently of the first question if the Court would have concluded that the terms of the Treaty cannot possibly be interpreted in a meaningful way, or that the parties to the Treaty by their conduct have indicated that the terms of the Treaty have lost their relevance. In that case a reverse situation presents itself: the answer to the first question is implicitly given by the preceding answer to the second question : the title over the Island determines the location of the boundary and it does so irrespective of the terms of the Treaty, but certainly not independently of the Treaty. In theory such a procedure would not be unthinkable.

14. In his award in the Island of Palmas case the sole Arbitrator, Judge Max Huber, stated that
"neighbouring states may by convention fix limits to their own sovereignty, even in regions such as the interior of scarcely explored continents where such sovereignty is scarcely manifested, and in this way each may prevent the other from penetration of its territory . . . If, however, no conventional line of sufficient topographical precision exists or if there are gaps in the frontiers otherwise established, or if a conventional line leaves room for doubt . . . the actual continuous and peaceful display of State functions is in case of dispute the sound and natural critιrium of territorial sovereignty." (Reports of International Arbitral Awards (RIAA), Vol. II, p. 840.)

15. In my opinion, the conditions mentioned in the Award are not met in the dispute before the Court. For the determination of the boundary the Special Agreement explicitly refers to the 1890 Anglo-German Treaty. There is no lack of sufficient topographical precision in the conventional [p1147] provisions, like e.g., in the Palena case (Argentine-Chile Frontier case, 38 International Law Reports, pp. 89 ff.). The Court does not have to find where the main channel of the River Chobe is located, it merely has to determine which of the two channels around Kasikili Island is or contains the main channel and what forms its thalweg. And the conventional line may leave room for doubt, but that doubt cannot be solved in a reasonable and arguable way by choosing a completely different approach which ignores the terms of the Treaty.

16. The inconsistency of Namibia's arguments in respect of its alternative claim is borne out by the fact that this non-Treaty-based claim rests on virtually the same grounds which it has submitted for its Treaty-based claim that the parties by their subsequent conduct have confirmed their agreement regarding the interpretation of the 1890 Treaty (see para. 71 of the Judgment).

17. These grounds are: continued control and use of the Island by the Masubia of Eastern Caprivi, the exercise of jurisdiction over it by the governing authorities in the Caprivi Strip, and the continued silence of the other Party and its predecessors. After examining Namibia's arguments the Court with good reason concludes that these facts do not constitute subsequent practice within the meaning of Article 31, paragraph 3 (b), of the 1969 Convention on the Law of Treaties (para. 75 of the Judgment).

18. These same arguments lie at the basis of Namibia's alternative claim that it has obtained sovereignty over Kasikili/Sedudu Island by acquisitive prescription (see para. 90 of the Judgment). The Court is of the view that Namibia has failed to prove that acts of State authority carried out with regard to the Island justify its claim to prescriptive title (paras. 98 and 99).

19. That conclusion, however, leaves unanswered one question. If Namibia had been able to prove that the requirements for acquisitive prescription, as referred to in paragraph 94 of the Judgment, had been fulfilled, would that not have constituted subsequent practice as well? Would it have been conceivable indeed to evaluate Namibia's claim to prescriptive title positively and at the same time to evaluate its claim concerning subsequent practice negatively? In my view that would mean that the Court, after having found that according to the terms of the 1890 Treaty the boundary is in the northern channel, would have been expected to use its answer to the second question concerning the legal status of the Island in order to trump its answer to the first question. In my opinion it would be highly artificial to read the Special Agreement as enabling the Court to do so. [p1148]

20. In my view, therefore, the Court should have refused to entertain Namibia's alternative claim and should have declared it inadmissible.

II

21. I have voted in favour of paragraph 3 of the dispositif of the Judgment which deals with the use of the two branches of the Chobe around Kasikili/Sedudu Island and is based on the Court's finding that the Parties have undertaken commitments to one another in this respect.

22. It seems relevant to point out that these undertakings are part of the Kasane Communique of 24 May 1992, a document which has as its main element the agreement between the Parties to settle the boundary dispute peacefully. These undertakings therefore are indissolubly linked to the Parties' decision to have the boundary determined, first by a jointly appointed Team of Technical Experts and subsequently, after the failure of the Joint Team to reach a conclusion, by the International Court of Justice on the basis of the Special Agreement of 15 February 1996. In carrying out its task of determining the boundary and the legal status of Kasikili/Sedudu Island, the Court can and must consider the Special Agreement in its context together with the surrounding statements and circumstances.

23. In addition to what the Court has said in paragraphs 102 and 103, I wish to make some observations which could provide guidance to the Parties for further conduct and place their mutual relations in a wider perspective. These observations are based on recent developments of the rules and principles of international law concerning the uses of international watercourses and in particular those concerning the equitable and reasonable utilization of their resources.

24. Such considerations have no place in determining the boundary between the Parties. The Court cannot relocate or shift the boundary on such grounds if according to the terms of the Treaty it must be taken to be the thalweg of the northern channel. While reflecting the rules and principles of international law, referred to in the Special Agreement, these considerations can merely focus on the undertakings of the Parties entered into in the context of their efforts to settle the dispute peacefully and on their present and future relations. As the Court has observed: "It is not a matter of finding simply an equitable solution, but an equitable solution derived from the applicable law" (Fisheries Jurisdiction, l.C.J. Reports 1974, p. 33, para. 78; p. 202, para. 69).

25. The Chobe River around Kasikili/Sedudu Island can be said to be part of a "watercourse" in the sense of the 1997 Convention on the Law of the Non-navigational Uses of International Watercourses. [p1149] Article 2 (a) of that Convention gives the following definition of a water-course:

"'Watercourse' means a system of surface waters and groundwaters constituting by virtue of their physical relationship a unitary whole and normally flowing into a common terminus."

26. This idea of a watercourse-system as a unitary whole was already recognized by the Institut de droit international in its 1961 Salzburg Resolution on the utilization of non-maritime international waters (except for navigation) (Annuaire de ITnstitut de droit international, Vol. 49, Part II (1961), pp. 381 ff.). In this Resolution, which was adopted unanimously, the Institute referred to "waters which form part of a watercourse or hydrographic basin which extends over the territory of two or more States". In Article 2 the Institut observes that the right of a State to utilize waters which traverse or border its territory "is limited by the right of utilization of other States interested in the same watercourse or hydrographic basin", whereas Article 3 states that "if States are in disagreement over the scope of the right of utilization, settlement will take place on the basis of equity, taking particular account of their respective needs, as well as of other pertinent circumstances".

27. In 1966 at its Fifty-Second Conference the International Law Association adopted, with only eight abstentions, the so-called Helsinki Rules on the Uses of the Waters of International Rivers (ILA, Report of the Fifty Second Conference, Helsinki, 1966, London, 1967, pp. 484 ff.). These refer to the waters of an international drainage basin which in Article II is defined as "a geographical area extending over two or more States determined by the watershed limits of the system of waters, including surface and underground waters, flowing into a common terminus".
The Helsinki Rules are far more detailed than the Institut's 1961 Salzburg Resolution and in certain respects can be called a precursor of the 1997 United Nations Convention. With regard to the principle of equitable utilization Article IV states: "Each basin State is entitled, within its territory, to a reasonable and equitable share in the beneficial uses of the waters of an international drainage basin".

28. It can, therefore, be said that in doctrine there was already overwhelming support for the principle of the equitable utilization of shared water resources when in 1971 the International Law Commission included the topic "The Non-navigational Uses of International Watercourses" in its general programme of work.

29. From the pleadings in the present case it is clear that the waters around Kasikili/Sedudu Island are nearly exclusively used for tourist pur-[p1150]poses. Tourists are carried by flat-bottomed boats (mainly, but not exclusively in the southern channel) to view the wild animals in the Chobe Game Park south of the river, and on Kasikili/Sedudu Island to which these animals regularly cross. Such navigation as there is has virtually nothing to do with fluvial transport in the normal sense of the word "navigation", as this is understood to mean transport by boat in a river from one place to another. The use which is made of the waters around Kasikili/Sedudu Island is more similar to the non-navigational uses of watercourses in the sense of the 1997 Convention.

30. Already in 1929 the Permanent Court of International Justice stressed the community of interest for navigation purposes of all riparian States and the exclusion of any preferential privilege of any of them in relation to the others (Territorial Jurisdiction of the International Com-mission of the River Oder, Judgment No. 16, 1929, P.C.I.J., Series A, No. 23, p. 27). In the Gabcikovo-Nagymaros case the present Court observed that "modern development of international law has strengthened this principle for non-navigational uses of international water-courses as well, as evidenced by the adoption of the Convention of 21 May 1997 on the Law of the Non-Navigational Uses of International Watercourses by the United Nations General Assembly" (I.C.J. Reports 1997, p. 56, para. 85).

31. The 1997 Convention has not yet entered into force and it will take in all probability a number of years before the 35 instruments of ratification necessary for its entry into force have been deposited. Nor is there any indication that the Parties before the Court have the intention to become bound by its provisions.

This does not mean, however, that a number of the principles, which are formulated in the Convention, have not yet become part of the corpus of international law.

32. In paragraph 1 of its commentary on Article 5 of the 1997 Convention, which deals with the principle of equitable and reasonable utilization and participation, the International Law Commission observes:

"Article 5 sets out the fundamental rights and duties of States with regard to the utilization of international watercourses for purposes other than navigation. One of the most basic of these is the well-established rule of equitable utilization, which is laid down and elaborated upon in paragraph 1."

And the Commission continues by saying that

"a survey of all available evidence of the general practice of States, accepted as law, in respect of the non-navigational uses of international watercourses . . . reveals that there is overwhelming support for the doctrine of equitable utilisation as a general rule of law for [p1151] the determination of the rights and obligations of states in this field" (para. 10).

33. Both Article 5 of the 1997 Convention and Article IV of the 1966 Helsinki Rules seemingly contain a territorial limitation by providing that watercourse States (Helsinki Rules: basin States) in their territories are entitled to a reasonable and equitable share of the uses and benefits of an international watercourseFN1.

---------------------------------------------------------------------------------------------------------------------
FN1 In paragraph 2 of its commentary on Article 5, the ILC observes that this Article, although cast in terms of an obligation, also expresses the correlative entitlement.
---------------------------------------------------------------------------------------------------------------------

Both instruments, however, clearly reject the so-called "Harmon Doctrine" which embodies the claim that a State has the unqualified right to utilize and dispose of the waters of an international river flowing through its territory.

The comment on Article IV of the Helsinki Rules states that the Harmon Doctrine has never had a wide following among States and has been rejected by virtually all States which have had occasion to speak out on the point and it continues by saying that each basin State has rights equal in kind and correlative with those of each co-basin State.

34. By the commitments contained in the Kasane Communique of 24 May 1992 (see para. 102 of the Judgment) the Parties have implicitly recognized that the Chobe River around Kasikili/Sedudu Island is part of a unitary whole, irrespective of the exact location of the boundary as a result of the determination by the Court.

35. The southern channel does not all of a sudden turn into an internal water once it is decided that the northern channel is or contains the "main channel" in the terms of the 1890 Treaty, even if the former is wholly within Botswana territory. It continues to be part of a system of surface waters and groundwaters which by virtue of their physical relationship constitute a unitary whole.

36. In their future dealings concerning the uses of the waters around Kasikili/Sedudu Island the Parties should let themselves be guided by the rules and principles as embodied in the 1997 Convention and in the Helsinki Rules. They should keep in mind that, as the International Law Commission said, "the rule of equitable and reasonable utilization rests on sound foundations and provides a basis for the duty of States to participate in the use and development and protection of an international watercourse in an equitable and reasonable manner".

37. This rule has now been widely accepted both for the navigational and the non-navigational uses of international watercourses. For a further implementation of the rule, Article 6 of the 1997 Convention enumerates [p1152] in a non-exhaustive way the factors which are relevant to equitable and reasonable utilization.

38. It is clear that the use of the waters around Kasikili/Sedudu Island for tourist purposes has in the course of time become far more important from an economic point of view than the use of the Island itself, e.g., for cultivation purposes; this is also exemplified by the Kasane Communique. But even the present economic interest resulting from eco-tourism may be of a transient character. It would, therefore, be commendable if the Parties would place any further co-operation in a wider and more general framework. In this respect it may be recalled that in the Preamble to its 1961 Resolution the Institut de droit international observes that "in the utilization of waters of interest to several States, each of them can obtain, by consultation, by plans established in common and by reciprocal concessions, the advantages of a more rational exploitation of a natural resource".

(Signed) P. H. Kooijmans. [p1153]


DISSENTING OPINION OF VICE-PRESIDENT WEERAMANTRY


TABLE OF CONTENTS

 

 

Page

Part A

 

 

 

Introduction

1156

 

 

General approach to questions of interpretation arising in this case

1157

 

 

Article 31 of the Vienna Convention

1158

 

 

Indicia of occupation

1163

 

 

The significance of Masubian use and occupation

1164

 

 

Contemporaneous understanding of the Treaty as evidenced by the conduct of the Parties

1165

 

 

Evidence of common understanding

1165

 

 

Suggested contrary factors

1167

 

 

(a) The Eason Report, 1912

1167

(b) The Trollope-Dickinson arrangement, 1951

1167

(c) The 1984-1986 discussions resulting from the shooting inci­dent of 24 October 1984

1168

 

 

Ambivalence of other criteria

1170

Navigability as a criterion for interpreting "main channel"

1170

[p 1154]

 

The thalweg concept

1172

(a) Applicability of the concept

1172

(b) Implications of the concept

1173

 

 

The scientific evidence

1175

Cartographic evidence

1175

Equitable navigational use of boundary rivers

1177

Conclusion regarding the "main channel"

1178

 

 

Part B

 

 

 

Introduction

1179

 

 

1. Judicial responses to a boundary delimitation which involves dis­mantling or dividing an ecologically or culturally integral unit

1181

 

 

2. The scope for equity in boundary delimitation

1184

 

 

3. Treaties dealing with spheres of influence distinguished from treaties dealing with State boundaries

1185

 

 

4. Joint international regimes

1188

 

 

Conclusion

1194


[p1155]

1. The Court has analysed and assessed with great care the vast amount of historical and diplomatic information placed before it. Upon a detailed consideration of all this material, the Court has arrived at the conclusion that the northern channel of the River Chobe constitutes the international boundary between Botswana and Namibia, in terms of Article III (2) of the 1890 Treaty between Germany and Great Britain.

2. A cardinal feature in this complex of information is the long continued Masubian use and occupation of Kasikili/Sedudu Island from a period prior to the 1890 Treaty for upwards of half a century thereafter. Namibia uses this information for two distinct purposes. It argues that the conduct of both administrations in reference to this use and occupation corroborates its interpretation that Article III (2) of the Treaty refers to the southern channelFN1. It also argues that such use and occupation establishes an entirely independent Namibian prescriptive claim to sovereignty over the IslandFN2.

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FN1 Memorial of Namibia, p. 10, para. 32.
FN2 Ibid., para. 33.
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The entirety of this opinion concentrates on the first of these Namibian bases of claim.

3. On the central question of the legal significance of this use and occupation, I incline to a somewhat different approach to that adopted by the Court. This leads me to a different conclusion regarding the international boundary.

My reasons for concluding that the southern channel constitutes the international boundary are set out in Part A of this opinion.

4. Part B of this opinion deals with a different set of concerns.

Since my finding places Kasikili/Sedudu Island within the territory of Namibia, while the Chobe Game Park to the south falls within the territory of Botswana, it positions within two territorial jurisdictions what is essentially a single wildlife sanctuary — a sanctuary, moreover, which is one of the most prized wildlife habitats in southern Africa.

5. The Island is frequented, as far as one can gather from the pleadings, by a rich variety of wildlife. Elephant, hippopotamus, buffalo, lechwe, rhinoceros, giraffe, eland, baboon, lion, zebra, leopard, and fish eagle either frequent the Island or visit it from time to time. As the Island, together with the Chobe Game Park to the south, forms the natural habitat of this wildlife, my conclusion that the Island falls within the territorial jurisdiction of Namibia necessitates a consideration of the environmental principles drawn in by such a finding, without which this opinion would be incomplete. One of these is the principle of joint [p1156] regimes, a matter peripherally involved in the Court's stipulation of equal access to the navigational use of the river. However, my finding necessitates a more detailed examination of this concept, which the Court has so far-sightedly incorporated in its Judgment.

6. Thus, on the one hand, this case transports us back to the age of empire-building in Africa, and requires us to re-enter the time frame of that era in order to understand what Britain and Germany had really agreed upon when dividing the relevant African territories between them. On the other hand, it raises issues which project us into a vital new area of international law, the rapid development of which will be a feature of the international law of the future.

PART A

Introduction

7. This case turns upon the interpretation of Article III (2) of the 1890 Treaty between Germany and Great Britain. The sphere in which the exercise of influence is reserved to Germany is described as bounded by a line which runs eastward along the 18th parallel of south latitude "till it reaches the river Chobe, and descends the centre of the main channel of that river to the junction of the Zambezi" (emphasis added). The German version of the Treaty uses the term "Thalweg des Hauptlaufes" for the English words italicized.

8. Problems arise in this case because of the bifurcation of the River Chobe into two channels which run to the south and the north of the disputed Island and reunite thereafter. The legal ownership of the Island would depend on whether the northern or southern channel is considered to be the main channel. If the northern channel is the main channel, the Island would fall within the territorial jurisdiction of Botswana, while a determination that it is the southern channel would bring it within the jurisdiction of Namibia.

A central question therefore is the interpretation of the italicized English and the corresponding German expressions. Are they synonymous and, if they have different connotations, how does one interpret this clause?

9. I am inclined to the view that the German terms were intended to be synonymous with the English expression "centre of the main channel". Yet, the German word "thalweg" often carries additional technical connotations as well. However, whether one reads the two expressions as synonymous or whether one gives the word "thalweg" a different and special connotation, it seems to me, for reasons which will be amplified later, that they point in the direction of the southern channel being the boundary indicated by the Treaty. [p1157]

10. Since the terms used are not so explicit as to point definitively to one or the other channel of the river, it becomes necessary to derive assistance from such aids to interpretation as are permitted by the law relating to treaties. Inasmuch as the cardinal question involved is how the boundary was understood by the parties or their agents in the context of the period of the Treaty, i.e., 1890 and the years immediately succeeding, there is invaluable assistance to be derived from the way in which the authorities on both sides regarded the regular Masubian crossings of the northern channel. These movements occurred regularly for over 50 years after the Treaty, without the faintest suggestion from either side that they involved the crossing of an international boundary.

11. After outlining the relevant rules of treaty interpretation and the legal significance, in that context, of the Masubian use and occupation of the Island, I shall consider the implications of the phrases used in the Treaty, and the ambivalence of the other criteria that have been suggested for determining what is the main channel.

General Approach to Questions of Interpretation Arising in This Case

12. The first stage of any exercise in treaty interpretation is to interpret the words according to their ordinary meaning. Even at this initial stage, the task is complicated by the fact that the expressions used may carry a legal meaning and a scientific meaning as well. The normal rule of interpretation of documents that words are to be interpreted according to their ordinary meaning is naturally modified if those words also bear a technical meaning in the context in which they are used.

13. This case presents a classic instance of what the law relating to treaties would class as a situation where the ordinary or indeed the legal and scientific meaning of the words used leaves one in considerable doubt as to the correct interpretation. Either interpretation — that which regards the northern channel as the main channel or that which regards the southern channel as the main channel — can be supported by a wealth of scientific and circumstantial data, based upon different criteria such as breadth, depth and volume, which have no necessary ranking order among them. While not discounting the high scientific and technical expertise of the experts who have been called before the Court by both Parties, it is necessary to note that there is a limit to the assistance they can give in the determination of the question which is the main channel of the Chobe River.

14. Since the matter thus remains unclear, another basic rule of interpretation is called into play, permitting a court to look further into the way in which the parties or their agents in fact acted upon the document. Parties know best in what sense they used any particular words and, espe-[p1158] daily in the case of an old or ancient document, this helps the modern interpreter considerably.

15. In this opinion, I shall place particular emphasis on this approach, as the words used are capable of more than one construction, whether viewed according to the ordinary meaning of the words used, or according to their legal or technical meaning. Since the document we are con-sidering is over a hundred years old, the way in which the document was understood at the time is clearly a powerful aid to its interpretation.

16. In determining this rather obscure question so long after the date of the Treaty, it must be acknowledged that the meaning we are searching for must have been much more apparent to those dealing with it closer to the time. Who better than they would know which of the two channels was considered at the time of the Treaty to be the main channel?

17. I am not, in this context, directing my attention to Namibia's alternative claim of prescriptive occupation of Kasikili/Sedudu Island, in the years immediately following the Treaty. I am here concerned, rather, with determining what would be a reasonable construction of the ambiguous expression "main channel", having regard to the conduct of those who were closest in time to the Treaty. In the crucial period immediately following the Treaty, how was it acted upon by those who were closest not only in time, but also in fact, to its practical operation?

It is apparent that there could not have been an implementation of the terms of the Treaty in the period immediately following the Treaty, in a manner which ran contrary to the sense of the two administrations as to what the Treaty meant.

18. I may add that contemporaneous conduct in relation to the Treaty is especially important in this case in the light of the fact that observations regarding the various qualities of the river — whether they be breadth or depth or volume of flow — can vary considerably over a period of a hundred years, and could depend very much on the time of observation, be it the wet season, the dry season or any other. The sense in which the Treaty was understood contemporaneously is the best index to what was actually intended, and any search for clarification of the terms used must focus intensely on this aspect.

Article 31 of the Vienna Convention

19. This brings me to a consideration of Article 31, paragraph 3(b), of the Vienna Convention, which has been the subject of detailed written and oral submissions by both Parties. Namibia has contended that it refers to "any subsequent practice . . . which establishes the understand-[p1159] ing of the parties regarding its interpretation"FN3, and that it therefore extends to conduct that takes the form of silence or inaction.

---------------------------------------------------------------------------------------------------------------------
FN3 Memorial of Namibia, Vol. I, p. 65, para. 177 (emphasis supplied).
---------------------------------------------------------------------------------------------------------------------

20. Botswana has resisted this contentionFN4, arguing that the Court should be cautious in the face of this suggestion, and that the meaning of the word "agreement" should not be thus watered down. Botswana has also argued that:

---------------------------------------------------------------------------------------------------------------------
FN4 Counter-Memorial of Botswana, Vol. I, p. 84, para. 238.
---------------------------------------------------------------------------------------------------------------------

"In the present case the whole point is that the acts alleged to constitute relevant acts of jurisdiction by Namibia are intended to constitute an independent source of title, that is, on the basis of prescription."FN5

------------------------------------------------------------------------------------------------------------
FN5 CR 99/13, p. 57.
------------------------------------------------------------------------------------------------------------

21. This submission does not accord with the submission of Namibia that it was relying upon this evidence for a twofold purpose. The establishment of prescriptive title through this evidence was only one of them.

The other, on which I concentrate in this opinion, was the question whether the silence or inaction of Botswana and its predecessors, in the face of regular use and occupation of the Island by the Masubian people, is evidence of an understanding of the Parties that the boundary referred to in the Treaty was the southern and not the northern channel.

22. Since the question before us is what the main channel was considered to be over a century ago, and since modern scientific evidence was not available then, one must turn to contemporaneous indicia. People living in the vicinity of the river, as well as those who had administrative authority over the area, would have had a far better understanding as to which was considered to be the main channel for practical purposes. The conduct of colonial officials, in particular, in relation to matters involving the boundary, would give us a valuable insight into the contemporaneous view as to which channel constituted the boundary. Here is a practical indicator of the Parties' understanding of the Treaty, which cannot be discounted or ignored. Indeed, it would seem strange, if not unrealistic, to give to the Treaty a meaning which does not accord with the contemporaneous understanding of the Treaty by the very officials who were called upon to administer it.

23. I accept Namibia's submission that the word "agreement" in Article 31, paragraph 3 (b), of the Vienna Convention can be read in the sense of "understanding", and can therefore cover silence and inaction as [p1160] well. This view derives support not only from the general law relating to the interpretation of documents, but also from the travaux prιparatoires of the ConventionFN6. In paragraph 49 of its Judgment, the Court likewise gives its support to the view that the Parties' understanding of the Treaty is the basis for the importance of subsequent practice.

---------------------------------------------------------------------------------------------------------------------
FN6 See the remarks of the Special Rapporteur, in discussing the comments by governments on the ILC Draft, 1964, that the ILC intended that evidence of subsequent practice indicating a "common understanding" should be taken as an "authentic interpretation comparable to an interpretative agreement" (The Vienna Convention on the Law of Treaties, Travaux Prιparatoires, Dietrich Rauschning, ed., 1978, p. 247, para. 18).
---------------------------------------------------------------------------------------------------------------------

24. The substitution of the word "agreement" for the word "understanding", which was contained even in the International Law Commission's penultimate draft, occurred in the context of bringing the English text into line with the French, Russian and Spanish textsFN7. The word "agreement" in the Convention bears a meaning analogous to the French and Spanish "accord" or "acuerdo", respectively, and does not therefore rule out an understanding which may not be couched in the form of a verbal agreementFN8. In the words of Sir Humphrey Waldock:

---------------------------------------------------------------------------------------------------------------------
FN7 See United Nations Conference on the Law of Treaties, First Session, 26 Mareh-24 May, 1968, 1969, p. 442, para. 29.
FN8 Indeed, English speaking delegations appeared content with the word "understanding". Thus Australia and the United States had introduced an amendment which, while retaining the words "understanding", sought to introduce the word "common" before it ( United Nations Conference on the Law of Treaties, supra, p. 442, para. 32).
---------------------------------------------------------------------------------------------------------------------

"The word 'understanding' was chosen by the Commission instead of 'agreement' expressly in order to indicate that the assent of a party to the interpretation may be inferred from its reaction or absence of reaction to the practice."FN9

------------------------------------------------------------------------------------------------------------
FN9 H. Waldock, doc. A/CN.4/186 and Add.1-7. "Sixth Report on the Law of Treaties", 2 Internationa/ Law Com. (1966), p. 99.
------------------------------------------------------------------------------------------------------------

The French and Spanish versions used the words "accord" and "acuerdo", which themselves do not necessarily bear the meaning of an agreement expressly made in so many wordsFN10. The word "agreement" in Article 31, paragraph 3 (b),oi the Convention must not therefore be interpreted to be restricted to a verbal agreement. It could include an understanding manifested by conduct.

---------------------------------------------------------------------------------------------------------------------
FN10 See Le Grand Robert de la Langue Franηaise, 1992, defining "accord" as "Ιtat qui rιsulte d'une conformitι ou d'une communautι de sentiments, de pensιes, de volontιs"; Marνa Moliner. Diccionario de uso del espaρol, 1988. defining "acuerdo" as "conformidad de pareceres entre dos o mαs personas".
---------------------------------------------------------------------------------------------------------------------

25. What has to be taken into account together with the context is "any subsequent practice in the application of the treaty establishing the [p1161] understanding of the parties regarding its interpretation"FN11. I refer also to the Beagle Channel Arbitration where the Court of Arbitration observed:

---------------------------------------------------------------------------------------------------------------------
FN11 Ian M. Sinclair, The Vienna Convention on the Law of Treaties, 1973, p. 71 (emphasis added).
---------------------------------------------------------------------------------------------------------------------

"The Court cannot accept the contention that no subsequent conduct, including acts of jurisdiction, can have probative value as a subsidiary method of interpretation unless representing a formally stated or acknowledged 'agreement' between the parties. The terms of the Vienna Convention do not specify the ways in which 'agreement' may be manifested."FN12

------------------------------------------------------------------------------------------------------------
FN12 Case concerning a dispute between Argentina and Chile concerning the Beagle Channel (1977), United Nations, Reports of International Arbitral Awards, Vol. XXI, p. 187, para. 169.
------------------------------------------------------------------------------------------------------------

The ample jurisprudence of this Court relating to subsequent practiceFN13 also shows that "the way in which the parties have actually conducted themselves in relation to the treaty affords legitimate evidence as to its correct interpretation"FN14.

---------------------------------------------------------------------------------------------------------------------
FN13 See, for example, Corfu Channel, I.C.J. Reports 1949, p. 25; Temple of Preah Vihear, I.C.J. Reports 1962, pp. 33-35; South West Africa, I.C.J. Reports 1971, p. 22; Military and Paramilitary Activities in and against Nicaragua, I.C.J. Reports 1984, pp. 408-413.
FN14 Sir Gerald Fitzmaurice, The Law and Procedure of the International Court of Justice, Vol. I, 1986, p. 357.
---------------------------------------------------------------------------------------------------------------------


26. For the purposes of the case before us, the words "any subsequent agreement" seem to me to refer to any consensus or common understanding in regard to how the words in question are to be viewed. The word "agreement" here is not restricted to a subsequent agreement in the sense of a fresh verbal agreement superimposed upon the original. It also embraces a consensus or common understanding, as shown by conduct, regarding its interpretation or application. Such conduct can take the form of action or inaction, affirmation or silence. I uphold the Namibian contention in this regard, and do not think it waters down the meaning of the term "agreement", as Botswana contends.

27. In other words, what we are looking at is not a variation of the Treaty by another agreement, but a consensus or common understanding between the Parties (as manifested by conduct, which may include action or inaction) as to how the words of the Treaty were interpreted and acted upon. In the words of Sir Gerald Fitzmaurice:

"conduct usually forms a more reliable guide to intention and purpose than anything to be found for instance in the preparatory work [p1162] of the treaty, simply because it has taken concrete and active, and not merely verbal or paper, form"FN15

------------------------------------------------------------------------------------------------------------
FN15 Fitzmaurice, op. cit., p. 357.
------------------------------------------------------------------------------------------------------------



Further, "there is no doubt about the standing of [this] principle, as an independent principle, which, in a proper case, it may be not only legitimate but necessary to make use of'FN16.

---------------------------------------------------------------------------------------------------------------------
FN16 Ibid., p. 359 (emphasis added).
---------------------------------------------------------------------------------------------------------------------

This approach does not involve an attempt to move away from the text of the Treaty, as suggested by BotswanaFN17, but rather an attempt to call in aid the conduct of the parties as a means of understanding the actual terms of the Treaty.

---------------------------------------------------------------------------------------------------------------------
FN17 Counter-Memorial of Botswana. Vol. I, p. 85, para. 240.
---------------------------------------------------------------------------------------------------------------------

28. I stress, of course, that resort to subsequent practice, as showing contemporaneous understanding of the treaty, can only be had when the ordinary meaning of the words used in the Treaty is not sufficiently clear — as is pre-eminently the situation in the present case. Words so charged with ambiguity as those under consideration here demand the use of supplementary means of interpretation, and contemporaneous understanding ranks high among them.

29. We are not here interpreting or applying a legal concept, in which case intertemporal principles might, in certain cases, attract the meaning that concept bears at the time of interpretation. Rather, we are here examining a question of fact as to which of the two channels was considered by the parties at that time to be the main channel. This principle of contemporaneity is one of the important principles of treaty interpretationFN18, and is not, I think, given its proper effect by taking into account, as the Court has done, the attitude of the Parties more than 50 years later, when political and other circumstances may well have necessitated a change of administrative policy from that which had been evidenced for the half century immediately following the Treaty.

---------------------------------------------------------------------------------------------------------------------
FN18 Fitzmaurice, op. cit., p. 359.
---------------------------------------------------------------------------------------------------------------------

30. Colonial administrations were specially sensitive, in the period of colonial rivalry, to incursions upon their territory from the territory of another colonial power. This would be expected to be particularly so at the time a treaty is concluded which defines their respective areas. At that time, the administrative authorities in the border regions, even though thinly spread, would be specially on the alert to incidents of use and occupation of the territory which are contrary to their contemporaneous understanding of what the treaty defines. If, indeed, there are such incidents and, as in this case, they are openly conducted, the administrative authorities would naturally register their concern. If, on the contrary, [p1163] they are aware of significant acts pointing to a particular understanding of the Treaty, and take no steps indicative of a different understanding, the natural conclusion to be drawn from such conduct is that such acts of use and occupation accorded with their contemporaneous understanding of the Treaty.

Indicia of Occupation

31. The use and occupation of this territory by Caprivi residents must be considered in the context of the particular geographical characteristics of the region and contemporary modes of human use and occupation of such territory.

We must not look for indicia of occupation in terms of settled housing or ordered agriculture, burial sites, or schools, for the very nature of this terrain prevented settled habitation in the manner known to Western jurisprudence and tradition. At best there would have been temporary occupation in makeshift huts from time to time as the rains and the climate determined. Such mud huts as there were would tend to be washed away during floodtime, for they were not constructed for permanent occupation. Even agricultural holdings could have been at best of a rather haphazard variety as compared with the holdings one is accustomed to in settled societies. Aerial photographs likewise would not reveal the ordered patterns of cultivation one is accustomed to see in cultivated agricultural land.

Factors such as these must be taken into account in assessing the inferences we could draw regarding Masubian occupation of the Island when the floods of each year had subsided.

32. Quite apart from the flood factor, there may well have been a lack of regularity in Masubian occupation of this territory, as is characteristic of a society which does not follow a regular routine year in and year out. Concepts of settled occupation, in default of which a territory is deemed unoccupied and even res nullius, which traditional principles of international law have led us to expect, must consequently be discarded in approaching a case such as the present. One recalls, in this context, judicial observations such as those in the Legal Status of Eastern Green-landFN19, holding that even slender proof may satisfy a court of the exercise of sovereign rights in cases of thinly populated or unsettled territory, where the other party cannot make out a superior claim.

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FN19P.C.I.J., Series AIB, No. 53, p. 46.
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[p1164]

The Significance of Masuhian Use and Occupation

33. Was the Masubian use and occupation of this territory, in the years immediately succeeding the Treaty, an occupation that was merely permissive, under some external authority, or was it resorted to on the basis that the occupiers felt entitled to such occupation without seeking the permission of any external authority?

If the latter was the case, their occupation must be presumed to be occupation under the State of which they were the subjects, rather than under any other State which claimed to have authority over the territory.

34. This approach may have its limitations, as the acts of occupation of the Masubia of the Caprivi Strip were not sovereign acts, but yet such legal benefit as might accrue from them must enure to the benefit of their sovereign authority rather than any other. This would be especially so if the occupation was an organized occupation under their chiefs rather than sporadic acts of occupation by individuals. In fact, the evidence indicates that the tribesmen attached great sentimental value to the Island which was regarded as a seat of chiefly authority, and that such occupation was part of the living tradition of their tribe.

35. Namibia argues that

"the Masubia of Caprivi had occupied and cultivated Kasikili Island from before the conclusion of the 1890 treaty until well into the second half of the present century and that Namibia's predecessors in title had continuously exercised jurisdiction over the area with the full knowledge of Botswana and its predecessors and without any official objection or protest from them until 1984"FN20.

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FN20 Counter-Memorial of Namibia, Vol. I, p. 40, para. 83.
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I believe there is no dispute regarding Masubian cultivation of the Island until 1947, allowing for such occasional intervals as were necessitated by climatic conditions. I believe the evidence supports the view that, from 1890 to 1947, such cultivation during the period when the Island was not flooded was a regular feature.
36. Colonial governments depended heavily on chiefly authority at a local level, and the claims and movements of chieftains were not matters of indifference to them.

What do we infer from this?

This may not have been occupation by a sovereign government such as is necessary for the acquisition of title by adverse prescription, though it could come close to such an interpretation. However, it was an occupation of the land of which the administrations on both sides were not [p1165] unaware. If this occupation was in disregard of the 1890 Treaty, one would have expected the Government of Botswana or its predecessors to lodge a protest, or at least to make it clear that the Masubia were there on sufferance. There is no evidence of any such action on Botswana's part.

Contemporaneous Understanding of the Treaty as Evidenced by the Conduct of the Parties

37. For the purpose of assessing the Parties' understanding of the Treaty, I now move on to a consideration of the factual material placed before the Court regarding official conduct on both sides. In doing so, I stress that what is most important to the legal question I am addressing is the common understanding of the two administrations in the years immediately succeeding the Treaty, and not during periods half a century or more after the Treaty.

38. Changes of official attitude that occurred at a later period, e.g., in 1947 or thereafter, throw little light on how the Parties understood the Treaty at the time it was entered into, or shortly thereafter. New policy orientations, and indeed new configurations of political power, may well have intervened half a century or more after the Treaty, having regard to the profound changes that took place in the region. For these reasons, I differ from the Court's conclusion of absence of agreement, based upon events between 1947 and 1951 and, indeed, thereafterFN21.

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FN21 Judgment, para. 63.
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Evidence of Common Understanding

39. In the light of the nature of Masubian occupation, as discussed earlier, I proceed to set out a summary of what can be gathered from the material before us, in regard to the common understanding of the Treaty in the years immediately following it. In doing so, I start with some of the findings of the Court as set out in paragraph 62 of the Court's Judgment.

— Prior to 1947, no differences had arisen between Bechuanaland and the power administering the Caprivi Strip with regard to the boundary in the area of Kasikili Island.

—It appears that, on the basis of the maps available at the time, the boundary had until then been supposed to be located in the southern channel of the Chobe. [p1166]

—While in 1948 a local official from Caprivi and a local official from Bechuanaland came to the conclusion that the main channel was the northern one, at the same time they noted that since at least 1907 use had been made of the Island by Caprivi tribesmen without objection by the Bechuanaland authorities, and that that situation still continued.

— It was subsequently, after consulting London, that the higher authorities in Bechuanaland took the view that the boundary was located in the northern channel.

Such subsequent action, taken nearly 60 years after the date of the Treaty, can scarcely be used to help in showing how the Parties understood the Treaty, especially where their earlier conduct points to a different understanding.

40. One should also take into account that

— Masubia use and occupation of the Island was of as significant a nature as the terrain and climatic conditions allowed.

— Masubia use and occupation included even the residence of a chief and a well organized village community and a school, factors of much significance when we consider that such occupation was never challenged by an administration whose successors claim that this was their territory, and did not raise objections thereto until nearly 60 years after the Treaty.

—One of the initial acts of the first German Imperial Resident, Streitwolf, was to install the Masubia chief, Chikamatondo, who was to be responsible to him for the areaFN22.

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FN22 Memorial of Namibia, Vol. I, p. 9, para. 28.
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— In later years, the Masubia chief himself lived on the Island, and held his court there.

As already observed, Botswana's contention that the "subsequent conduct" argument is one grounded in acquisitive prescriptionFN23 does not take account of the fact that these are in fact two separate arguments. Factors throwing light on the contemporaneous understanding of the Treaty can be considered quite apart from their weight as supporting acquisitive prescription.

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FN23 Reply of Botswana, Vol. I, p. 55, para. 157.
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41. For these reasons, there is sufficient material from which to conclude an understanding on the part of the Parties to the Treaty, as evidenced by their practice for upwards of half a century, that they regarded the southern boundary of the River Chobe as the main channel. [p1167]

Suggested Contrary Factors

42. Some items of fact asserted by Botswana to evidence non-recognition of Namibian sovereignty need now to be examined.


(a) The Eason Report, 1912

43. Botswana relies heavily on Captain Eason's report in which he stated that "undoubtedly the North should be claimed as the main channel". Here was an occasion where the precise question now in issue was specifically brought to the notice of the governmental authorities in question, with a categorical recommendation that a claim should be made. It must be presumed that this assertion received official consideration. Yet no such claim was made. A reasonable inference is that higher officials considered this recommendation and took a considered decision not to act upon it.

This is confirmatory of the Namibian position rather than a rejection of it. Moreover, the instructions to Eason of Lieutenant Colonel Panzera, the Resident Commissioner in Bechuanaland, reveal that the matter was in fact under consideration by the Bechuanaland authorities and that they were seeking a solution to the question which was the main channel. This reinforces the conclusion that the authorities took a definite decision not to act on the conclusions of Eason, thus administratively rejecting the recommendation that a claim be made that the northern channel was the main channel.

Colonel Panzera instructed Eason that the question under consideration could only be solved by following up the deepest channel in which there is the strongest current, and that the width of the channel was not the matter in issue. Eason's observations made during the dry season could hardly have been observations in accordance with these guidelines, for during the dry season there is scarcely any current in either channel. Indeed, Eason's observations were made at the end of an exceptional drought during the previous 12 monthsFN24.

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FN24 Memorial of Botswana, Vol. Ill, Annex 15, p. 226, para. 2.
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(b) The Trollope-Dickinson arrangement, 1951

44. This relates to a period more than 60 years after the Treaty, and does not have the same relevance to contemporaneous understanding as events closer to the Treaty. I shall still examine it in view of the importance attached to it by Botswana. [p1168]

The Botswana Memorial places much reliance on what is stated to be a "joint report" by Major Trollope, the South African magistrate for the Eastern Caprivi, and Noel Redman, the District Commissioner for the Bechuanaland Protectorate. The report, which does not state the reasons for its conclusions, states that the main channel lies in the waterway which would include the Island in question in the Bechuanaland Protectorate.

Yet, as with the Eason Report, there are circumstances which adversely affect the weight of this opinion.

(i) After the receipt of the joint report, matters between the two governments were not settled on this basis, but the officials "agreed to differ on the legal aspect regarding Kasikili Island"FN25. No advance was therefore made on the pre-existing position.

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FN25 Counter-Memorial of Namibia, Vol. IV, Ann. 71, para. 7 (a). This conclusion emerged from correspondence between Trollope and Dickinson, Redman's successor, who came to a "gentleman's agreement" in which they agreed to let the issue rest in obscurity (ibid., para. 8, and Ann. 73, para. 4).
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(ii) Trollope himself stressed the aspect of use and occupation as indicating that the Island was part of the Caprivi StripFN26.

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FN26 Counter-Memorial of Namibia. Vol. I, p. 47, para. 104.
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(iii) The Legal Advisers of the Bechuanaland Protectorate seem to have proceeded on the basis that the Island had never been treated as part of the Bechuanaland Protectorate and therefore "shall be deemed not to be included, and never to have been included, in the [Bechuanaland] Protectorate"27. There could hardly be a more categorical rejection of the position contended for by Botswana.

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FN27 Memorial of Botswana, Vol. Ill, Ann. 28, para. 3 (b)\ Counter-Memorial of Namibia, Vol. I, p. 48, para. 104.
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(iv) The Report expressly leaves open the question of the impact of the use of the Island by Caprivi tribesmen since 1907 on the question of the ownership of the Island.

(c) The 1984-1986 discussions resulting from the shooting incident of 24 October 1984

45. I do not need to deal with these discussions as they were nearly a century after the Treaty, and can throw little light on how the Treaty was contemporaneously understood.

46. In the result, there appears to have been a long-standing use by Caprivi tribesmen of Kasikili/Sedudu Island, without any official protest or assertion of rights by the authorities of the British possessions to the south. The right of the Caprivi tribesmen to use the Island was undisputed not only by the Bechuanaland authorities, but even by the Bechuanaland tribesmen — as was noted by the Secretary for External [p1169] Affairs of South Africa in his reply of 14 February 1949, addressed to the Chief Secretary to the High Commissioner for BechuanalandFN28.

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FN28 Memorial of Namibia, Vol. IV, Ann. 65, also noted in the Court's Judgment, para. 59.
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47. The understanding that the Island was not Botswana territory appears to have been so deep-rooted that it carried over into the years immediately succeeding the achievement of Botswana's independence. Important evidence in this regard is the action of a Botswana magistrate in 1972 (six years after Botswana achieved independence) in acquitting three Caprivi tribesmen who had been arrested on Kasikili Island by game wardens of the Chobe National Park and detained in Kasane for five days. According to affidavits submitted by Namibia, the magistrate criticized the game wardens for arresting them on Caprivi territoryFN29.

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FN29 Counter-Memorial of Namibia, Vol. II, Ann. 24; Counter-Memorial of Namibia, Vol. I, pp. 42-44, paras. 87-90.
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48. Botswana denies this incident, stating that it depends only on the affidavits of the accused persons. However this may be, the occurrence of an incident of this nature is confirmed by the fact that in 1973 South Africa sent a protest note to the President of Botswana relating to the entry of armed Botswana officials into what it described as "Eastern Caprivi territory"FN30, and that Botswana did not reply to this communication, even though South Africa sent a follow-up inquiryFN31. The matter was thus taken up administratively at governmental level, with South Africa issuing a note on the matter to the President of Botswana. There was no assertion of rights by the Government of Botswana in reply.

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FN30 Counter-Memorial of Namibia, Vol. II, Ann. 26.
FN31 Ibid., Ann. 27.
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All this is far different from the judicial and/or governmental response that would have ensued had it been the official view in Botswana that this was Botswana territory.

49. These circumstances are sufficient to show the official perception of the position of the main channel from a period comparatively close in time to the Treaty to the period even after independence.

What is most important to note against this background of official attitudes is the openness of the manner in which the Masubia tribesmen had over the years for nearly half a century visited, lived in and cultivated this Island whenever the weather and river conditions permitted. They did this without acknowledgment of title under any external authority, but as part of their traditional lifestyle. This was a fact that was well known in the area and must be taken to have been particularly well known to the officials exercising jurisdiction over it. [p1170]

50. Against this background, the absence of contrary action by a State authority claiming title to the territory is difficult to reconcile with an understanding of the Treaty in any sense other than that it treated the Island as lying within the territory that fell to Namibia — a result presupposing a commonly accepted view on both sides that the "main channel", for the purposes of the Treaty, was the southern one.

In short, if one is attempting to understand the terms of an expression in the Treaty which is equally capable of two interpretations, there is an almost conclusive indication in all this conduct of the way in which the authorities on both sides of the border understood and interpreted the agreement. That understanding and interpretation are clearly indicative of the Island being considered without any objection or assertion to the contrary to be part of the Caprivi Strip.

51. I stress again that I am using this material in regard to use and occupation and non-protest by the rival State authority only as an aid to the understanding of the terms of the Treaty, in view of the ambiguity therein which needs to be resolved. I am not using it as evidence of prescriptive title. I stress particularly that this is not material on the basis of which the terms of the Treaty can be altered. It is only a basis on which the terms to the Treaty can be interpreted and better understood.

Although Namibia argues further that this record constitutes an independent title to sovereignty over the Island by operation of the doctrines of acquiescence, recognition and prescription, I need not go into this argument for the reasons indicated above.

Ambivalence of Other Criteria

52. Various criteria were suggested in the course of the argument for determining the main channel. Among these were navigability, the thalweg concept, greatest mean depth, depth at the most shallow point, greatest capacity, and velocity of flow.

I proceed however to make some observations on these aspects.

Navigability as a Criterion for Interpreting "Main Channel"

53. There seem to be strong arguments indicating that in the context of the river we are considering, namely the Chobe River, navigability is an inappropriate criterion for the determination of its main channel.

It is to be remembered that there was no uniform way in which at the period in question river boundaries were designated or understood. For example, as the Namibian Counter-Memorial points out, there were, in [p1171] the context of treaties fixing African river boundaries, a variety of expressions that were used:

1884 — "up the course of the Limpopo River . . ."
1891 — "the centre of the channel of the [River] Ruo"
"the mid-channel of that [Aroangwa] River"
"the centre of the main channel of the Sabi"
1898 — "the median line of the [Niger] river"
1899 — "the centre of the River Ruo up-stream"
"shall follow the Malosa River up-stream"
1911 — "the line of the thalweg of those [Ruo and Shire] rivers"
1912 — "the centre of the channel of the River Gaeresi"
1926 —"the middle line of the Kunene River, that is to say, the line drawn equidistant from both banks"FN32

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FN32 Counter-Memorial of Namibia, Vol. I, pp. 26-27, para. 57, citing examples from Ian Brownlie, African Boundaries: A Legal and Diplomatic Encyclopaedia, 1979.
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Some of these rivers were navigable. Some were not. The Chobe was largely non-navigable. There was no set rule of interpretation reading navigability into these phrases. To apply navigability as a criterion indiscriminately to all river boundaries, whether the river be navigable or not, does not seem to be appropriate.

54. One bears in mind in this context the known desire of the German empire to have access to the Zambezi. This was a general principle all colonial powers pursued as they desired the maximum freedom of movement to, from and within their territories. Yet this was at the time a rather theoretical concept, for the Zambezi was not a navigable river, at any rate near its junction with the Chobe, and the navigability of the Chobe along its entire length and for the greater part of the year was not even in contemplation.

55. Moreover, using navigability as a criterion does not accord with the principle that words should be given their ordinary meaning. I would not therefore give to the words "the main channel" a meaning which is dependent on the concept of navigability, which was not a dominant meaning in the minds of the drafters of the document.

56. In relation to navigation, it is to be noted that, even up to 1914, such navigation as there was on the Chobe River was done by dug-out canoes or mekoro and that even the colonial officials used no better craft33. Moreover, there was clearly no evidence of regular, scheduled commercial navigation34. Even as late as the 1940s when the much discussed timber venture of W. C. Ker was inaugurated, this was the first attempt at the use of the Chobe as a means of transport. However, there [p1172] is doubt as to whether Ker in fact set up such a service, and Namibia has stated in answer to a question by President Schwebel that it has not been able to find any evidence that W. C. Ker ever actually transported timber through the northern channel.

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FN33 Botswana's reply to Judge Fleischhauer's Question 1.
FN34 Ibid.
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57. For these reasons, definitive importance cannot be accorded to navigation as a criterion. I note also in this connection Namibia's answer to Judge Fleischhauer in which it stated that it has been unable to find a single reference to a boat of any kind at any period in history ever tra-versing the whole length of the Chobe River where it forms a common boundary between Namibia and Botswana.

There are limits therefore to the extent to which navigability can be used as a criterion for determining which was the main channel.

The Thalweg Concept

58. There has been much discussion in the course of the presentations before the Court regarding the applicability of the thalweg concept to this case. Botswana identifies the thalweg as one of the criteria by which to identify the main channel, defining the thalweg as "the channel most favourable to the movement of vessels proceeding downstream when the water is at its lowest"FN35

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FN35 Memorial of Botswana, Vol. I, p. 89, para. 205, citing Julius Hatschek, Outline of International Law, trans, by C. A. W. Manning, 1930, p. 130.
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This argument highlights the question whether the term was used in the Treaty as a synonym for "centre of the main channel", or whether it was used as a term with an independent meaning. I believe that the use of the term "thalweg" in the Treaty was not a use of it in any technical sense but, even if it were so used, it would enure to the benefit of Namibia.

(a) Applicability of the concept

59. If the thalweg concept is to be used in interpreting a treaty of 1890, it must first be established that the technicalities associated with the concept were generally recognized at the time. We cannot use the more developed concepts of a later time to interpret a treaty entered into more than a century ago.

The Namibian pleadings assemble 47 authorities who discussed the thalweg concept between 1820 and 1930FN36. These authorities represent a variety of views — that the thalweg should be the boundary in navigable rivers only; that it should be the boundary in all rivers; that it does not [p1173] apply at all; that it means the same as the median line ; that it was not a principle that was generally recognized; and that it was a principle which as yet was in the realm de lege ferenda. Even the proceedings of the Institute of International Law in 1887 reflect this uncertainty, for De Martens, the Rapporteur for the session concerning international rivers, did not include this provision in his project for the Institute as he said "ce principe n'est pas gιnιralement reconnu"FN37.

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FN36 See Counter-Memorial of Namibia, Vol. II, Ann. 9.
FN37 IX Annuaire de VInstitut de droit international (1887-1888), p. 173.
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60. An inference that can be drawn from all of this is that it was not a principle so widely accepted at the time as to vary the natural meaning of the words used in the Treaty.

However, even should the thalweg concept be deemed to be applicable, its implications do not necessarily enure to Botswana's benefit, as shown in the next subsection.

(b) Implications of the concept

61. Even if the principle were applicable, there is considerable authority in support of the proposition that the thalweg concept relates not merely to depth but also to the flow or current of the river. Indeed, some authorities would appear to indicate that considerations relating to depth are secondary to those relating to flow or current.

According to Westlake, for example, the thalweg is "the course taken by boats going down stream, which again is that of the strongest current"FN38.

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FN38 J. Westlake, International Law, Part. I, Peace, 1904, p. 141. Westlake points out that the older authorities had taken the middle line of the river as the true boundary in obedience to the Roman law relating to delimitation of properties, and that the thalweg was thought to have been first proposed at the Congress of Rastatt (1798-1799).
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L. F. von Neumann, likewise, describes it as "the line that is taken by ships going downstream, more precisely the centre of the downward current"FN39.

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FN39 L. F. von Neumann, Grundriss Des Heutigen Europδischen Vφlkerrechtes, 3rd ed., 1885, p. 45 (trans.).
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Other authoritative writing from around the same period may be cited for the same proposition. Fiore, for example, speaks of the line "ou les eaux sont les plus profondes et les plus rapides"FN40 — a combination of the concepts of depth and current.

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FN40 Pasquale Fiore, Le droit international, trans, from the Italian by A. Chretien, 1890, p. 205. A later edition accentuates the consideration of flow by defining the thalweg as determined by "the median line of the current and following precisely the course of water with the most rapid flow" (1911 ed., p. 503, trans, by C. Antoine).
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62. It is not difficult to perceive the reason for the blending of depth and current in the concept of the thalweg, for the "downway" as it literally meant, was for boats the path of the strongest current and not necessarily the path of the deepest channel. Of course depth was also [p1174] an important ingredient in the complex of factors that produced the strongest current.

63. There is significance also in the fact that the line it represented was the line of the "downway", i.e., for ships that went down the river, and therefore those in maximum need of using the maximum current. By contrast, ships going up the river needed the slowest current to fight against — a point very clearly made by WestlakeFN41.

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FN41 Westlake, supra, p. 141; see also p. 33, fn. 103, of Counter-Memorial of Namibia.
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64. In the case of the two channels of the Chobe, it is clear that the southern channel is not by any means to be disregarded from the point of view of its use for shipping. Those who operate boats on rivers know best the channels which suit them for downward navigation. The number of boats using the southern channel appears to exceed by far the number of those using the northern channel. Boatmen would know best which is the swiftest channel for this, and it is no accident that so many of them choose the southern channel.

Judged by this test as well, the southern channel has a very good claim to being regarded as the main channel of the Chobe.

It is not without significance also that, while the tourist boats use the southern channel almost exclusively, some of the boats returning from Kasane use the northern channelFN42 — an indication that the current in that channel is the slow channel that is suitable for up-river navigation.

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FN42 Counter-Memorial of Namibia, Vol. I, p. 19, para. 45.
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65. Another factor to be borne in mind is that mean depth cannot be the only criterion for navigability. A river which has very great depth along a very narrow channel would be quite unsuitable for navigation if the sides of that deep channel rise very steeply to present very shallow levels outside the narrow crevice of greatest depth. Boats, especially broad-bottomed boats, would not be able to use such a channel, however deep it might be. As Namibia has observed in its Counter-Memorial, "Passage through a channel is controlled by the point of minimum depth, because all craft must clear that point to traverse the channel."FN43

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FN43 Ibid,, para. 46.
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66. There are obstacles of this nature in the way of free use of the northern channel — in particular the sand bar at its entrance. By way of contrast, the entire length of the southern channel is of sufficient depth to accommodate the fiat-bottomed boats that use it at all times of the year. Nor does the southern channel dry out during the dry season, if one has regard to the calculations of Professor AlexanderFN44.

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FN44 Ibid., p. 20, para. 47. See Supp. Rep, sec. 12.
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[p1175 ]

The Scientific Evidence

67. If the term "main channel" had been used in a contemporary treaty, and we were seeking the true meaning of that term, scientific evidence on such matters as depth, volume, breadth, and flow would help us considerably. But the Treaty under examination is over a century old and, even if depth, volume, breadth and flow had been constant over the years, modern scientific criteria are not the indicia appropriate for determining what was commonly understood to be the main channel a hundred years ago.

I hence have considerable difficulty in reaching a definitive conclusion based upon the scientific evidence in this case.

68. In the first place, it is extremely complex and, considered in its totality, contains opposing views by equally credible and competent experts in the various fields covered. A plausible case can be made out for either viewpoint using the data furnished to the Court, and this leaves one none the wiser in the midst of all this expert information.

69. Secondly, I have grave doubts that the problem before the Court can in any event be resolved by scientific evidence. The question we are faced with is the meaning of an expression used by the Parties, which meaning has to be gathered not from quantitative statistics of volume and flow and depth, but rather from the Parties' own understanding at the time of the apparently simple language used in the Treaty. This was a non-technical understanding, not dependent upon expert scientific opinion or precise quantitative data.

70. Thirdly, even if the scientific evidence were applicable, it would be legal criteria that would determine which aspect if any of the vast amount of scientific data placed before the Court would be determinative. There are no clear cut legal principles for determining this which are sufficient to outweigh the principles of interpretation discussed already.

71. Fourthly, there is no definite principle for a ranking order among the various scientific criteria offered. Among these criteria are capacity (i.e, amount of flow), velocity of flow, mean depth, and depth at the shallowest point. It is not scientific principle but non-scientific factors that would determine the choice of the governing criterion. Moreover, one gets a different result depending on which criterion one employs.

Cartographic Evidence

72. There is support to be gained from the maps of the two administrations for the view that the understanding of the Treaty in the period succeeding the time of its execution was to the effect that the operative [p1176] branch of the river was that which placed the Island within Namibian territory. Indeed, the Court has foundFN45 that maps published subsequently to the 1890 Treaty, in so far as they showed the boundary at all, for a number of years placed the boundary in the southern channel. The 1933 Bechuanaland map and the 1949 South African map are among these.

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FN45 Judgment, para. 85.
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73. Maps can of course carry varying degrees of weight depending on their authorship and the circumstances in which they were made. Moreover, the scale of the maps is often so small as not to show clearly the particular area which is the subject of the dispute, while other maps which are sufficiently large can indicate the area of dispute in sufficient detail.

Of the 16 maps in Namibia's atlas, some are too small in scale to show Kasikili/Sedudu Island, but 12 are large enough to show the Island and they all show the Island as Namibia's, in the sense that they show the southern channel as the international boundary.

It is significant that among the maps showing the southern channel as the border are several sketch maps of the Bechuanaland Protectorate published by the British Colonial Office from 1912 to 1914 — a fact admitted by Botswana in its MemorialFN46 — and referred to in Namibia's Counter-MemorialFN47.

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FN46 Memorial of Botswana, Vol. I, paras. 270-272.
FN47 Counter-Memorial of Namibia, Vol. I, p. 63, para. 141.
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Of the 19 Colonial Office reports containing maps, 15 show the boundary on the south side of the Chobe and four on the north side.

74. The arithmetical preponderance is not so important as the fact that not in any of these maps — leave alone the majority — are the boundaries indicated in such a manner as to leave the disputed territory within the boundaries of the other State. This is scarcely consistent with the position that the Treaty was intended to treat the northern channel as the main channel. Rather, this statistic supports the view that the understanding of the Treaty was certainly not such as to place the Island in question within the territory of Bechuanaland — in other words that the understanding of Parties was that the main channel was the southern channel. Prominent among the British maps is the official British map of 1933 used up to 1965, one year before independence, which shows the Island within the Caprivi StripFN48.

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FN48 Map GSGS 3915 of 1933, Namibia Atlas Map IX; see also. Memorial of Namibia, Vol. I, p. 125, para. 305.
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75. Namibia likewise has the advantage of a number of official maps on the German side also indicating the southern channel as the boundary. Among these are Seiner's map, the principal large-scale map used by German officials in Berlin and in the field, from its publication until the
[p1177] end of German rule in NamibiaFN49. It was sent by Germany to the British Foreign Office during the 1909-1914 negotiations relating to the southern boundary of the Caprivi Strip. The boundary is there shown placing Kasikili Island very clearly on the Namibian side. So, also, is the case with von Frankenberg's mapFN50. Adding to the weight of these maps is the South African Official Map of 1949FN51, the principal map used by South Africa until Namibian independence.

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FN49 Memorial of Namibia, Vol. I, p. 121, para. 294; see also Counter-Memorial ofNamibia, p. 69, para. 155.
FN50 Memorial of Namibia, Vol. I, p. 123, paras. 298-299; Counter-Memorial of Namibia, Vol. I, p. 70, para. 156.
FN51 Counter-Memorial of Namibia, Vol. I, p. 75, para. 162.
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76. The cartographic evidence thus seems to me to be in favour of the Namibian position, and of the contemporaneous understanding of the Parties, as outlined earlier in this opinion.

Equitable Navigational Use of Boundary Rivers

77. It is an important principle of riparian law that equitable factors also play a significant role in determining riparian boundaries, where there is room for a difference of opinionFN52.

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FN52 On the "overwhelming support of the international community" for the doctrine of equitable utilization and the limitations of territorial sovereignty in relation to riparian boundaries, see M. Fitzmaurice, in Legal Visions of the 21st Century, Anthony Anghie and Garry Sturgess (eds.), 1998, pp. 428-436.
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One of the principal uses of rivers is navigation and transport and the need especially to use rivers for transportation downstream. That was probably the rationale underlying the thalweg principle, already referred to in this opinion.

There is another factor as well that is relevant to this aspect. Since the vast bulk of the tourist traffic, which is the most vital traffic carried on either channel, uses the southern channel, this is a substantial source of revenue to both countries.
A riparian boundary is meant to afford to both riparian States equal use and benefit from the boundary river. If the boundary is decided to be the channel which is not suited to carry the bulk of the vessels using the river, both States would not be able to use the river equitably. To hold in the present case that the northern channel is the boundary would, by denying Namibia the use of the southern channel, cause far greater loss to Namibia than the loss that would ensue to Botswana if the southern channel were held to be the boundary, in which case Botswana would be denied only the use of the northern channel which is comparatively of far less value. [p1178]

This important use of the river must be equitably shared by both riparian States. This use is particularly essential to the economy of both countries. As Namibia informed the Court at the oral hearingsFN53, tens of thousands of tourists from all over the world come to Namibia to visit its game parks, and the same is no doubt true of Botswana. The use of the southern channel to observe the wildlife on Kasikili/Sedudu Island would be a natural and important part of the agenda of the tourists in both countries.

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FN53 CR 99/10, p. 15, para. 18.
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78. The evidence we have before us indicates that the vast majority of tourist vessels — including the redoubtable Zambezi Queen — do not use the northern channel. Most of them use the southern one. Apart from this being a strong indication of the thalweg being in the southern channel, it also raises the equitable consideration that both riparian States should have an equal right to use this main navigational route. To consider the northern channel to be the main channel is to deprive Namibia of the valuable use of this southern channel which is capable of taking all the traffic which the northern channel cannot take. On the other hand, if the southern channel is considered the boundary, both States would have equal use of this main means of navigation. The loss or inconvenience to Botswana in not having the free use of the northern channel would be comparatively minor as compared to the loss to Namibia if it could not use the southern channel.

The principal loss and inconvenience to Botswana would be not in regard to navigation, but in regard to the tourism and preservation of wildlife which would ensue from the fact that the teeming wildlife on the Botswana side has habitually crossed over to the Island and that the Island is in a sense an integral part of this wildlife preserve. This aspect is considered in Part B of this opinion.

Conclusion Regarding the "Main Channel"

79. My conclusion is therefore that the southern channel must be regarded as the main channel for the purposes of the 1890 Treaty. This would leave Kasikili/Sedudu Island de jure within the territory of Namibia.

Having reached this conclusion, I am obliged to examine certain consequential legal questions which would arise from such a decision. They do not arise in this form in the context of the Court's Judgment, but need to be examined in this opinion as a necessary consequence of my conclu-[p1179]sion that the southern channel is the main channel. These legal questions are examined in Part B of this opinion.

Part B

Introduction

80. Having arrived at my conclusion that the main channel is the southern one, and hence that Kasikili/Sedudu Island must be considered part of Namibian territory, 1 now address a resultant question which will confront international law with increasing intensity in the future — the tension between principles of territorial sovereignty and principles of ecological protection which involve a fiduciary responsibility towards the ecosystems of the States concerned.

The teeming wildlife of this area makes it one of the prized game parks of Africa. Its protection is a matter of international concern which cannot be permitted to recede from view in the midst of conflicting claims of the contending Parties. This raises in pointed form the scope of judicial responsibility when environmental issues straddle the boundaries demarcated by the Court.

Indeed, this aspect was addressed in the pleadings, and it was argued on behalf of Botswana that

"if the Court were to rule in favour of Namibia, the decision would immediately remove the Island from the range of the wildlife, as they would be hunted down on the Island, as was done in the rest of the Caprivi. Thus, in the interest of conservation, and for all the other reasons to be advanced by Botswana in this case . . . the Court should rule in favour of Botswana. By so doing, the Court would make a clear statement on conservation to all mankind, including Namibians."FN54

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FN54 CR 99/6, p. 22
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The circumstance referred to does not per se amount to a ground for ruling in favour of Botswana, but it does raise a serious consideration which cannot be ignored.

81. My finding that the Island falls within Namibian territory thus requires me to address this argument, having regard to the compelling weight which modern international law attaches to environmental considerations, reinforced as it is by such conventions as the 1992 Convention on Biological Diversity (the Biodiversity Convention) signed and ratified by both Parties to this case, and other conventions such as the Convention on International Trade in Endangered Species (CITES), and the 1971 Convention on Wetlands of International Importance Especially [p1180] as Waterfowl Habitat (Ramsar Convention). The problem adverted to by Botswana is one which can be suitably addressed in the light of the great progress that has been made by modern international law in the structuring of joint regimes for the conservation of environmentally important sites.

The fact that the entity to be preserved is a "common heritage" or at least a "common concern"FN55 of humankind, reinforces the judicial duty in this regard — a duty which naturally reaches further than that of surveyors and cartographers who depict stipulated geographical features on the ground.

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FN55 See Biodiversity Convention, 1992, Preamble, para. 3.
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International law is now in too mature a state of development to carry out its tasks of boundary delimitation in mechanical fashion. It cannot interpret and apply a boundary treaty in abstracto, an approach which may have been possible in an earlier age. In the environmental field, the growing recognition of world heritage values prevents such a rigid attitude from being followed.

82. The present case offers us an instance of a situation which is likely to come before the courts more often in the future. The evolution of legal guidelines for such situations is not a venture into new legal territory, for many precedents already exist. I see it as inevitable that the future will bring before international tribunals other situations as well in which there are interests of a universal nature which need to be preserved, and where two or more States may need to co-operate to ensure that some important aspect of the universal heritage of humanity is not diminished.

83. As we enter an era in which active co-operation, rather than passive co-existence, becomes a keynote concern of international law, it is inevitable that such concerns will receive increasing judicial consideration. It helps in this case that the Court is required to decide "on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law" (emphasis added) the question of the true boundary between Botswana and Namibia in the disputed area of the Caprivi Strip. The "rules and principles of international law" comprise well-recognized principles of environmental law which cannot be ignored.

It is significant, moreover, that the Court is asked to determine not merely the boundary between Namibia and Botswana, but also the legal status of the Island. This enables the Court to create a special legal regime for the Island, should it choose to do so — an aspect that becomes especially important in the event of a finding that the Island belongs to Namibia.[p1181]

84. We are here dealing with the protection and enjoyment of a unique part of the world's wildlife heritage which, from all that we have heard in the course of the case, represents a remarkable place of congregation of a rich variety of wildlife — a place where they meet and feed and breed. In the words of Professor Alexander:

"There are very few wildlife areas in southern Africa where such a variety of game and bird life can be seen from such close quarters as along the southern channel of the Chobe river at Kasikili Island."FN56

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FN56 Counter-Memorial of Namibia, Vol. Ill, p. 34, para. 11.9.
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He also confirms the statement in the Botswana Memorial that "[t]he grazing on the island is excellent and there is a daily elephant migration to the island"FN57. Such places are critical to the maintenance of biodiversity which, as the Biodiversity Convention has proclaimed is, if not a common heritage of humankind, at least a common concern of humankind.

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FN57 Ibid., para. 11.2; Memorial of Botswana, Vol. I, p. 14, para. 32.
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85. The aspect I am now addressing brings to the forefront some vital legal issues relevant to the delimitation of boundaries. I shall deal with four of them in the following order:

1. The function of the Court when delimitation of a boundary line involves the dismantling or division of an ecologically integral unit of biodiversity.

2. The role of equity in the practical problems attendant on delimitation.

3. The relevance of the distinction, if any, between colonial treaties that specifically designate boundaries and colonial treaties indicating spheres of influence.

4. The notion of joint regimes over ecologically vital portions of territory which, despite the ecological unity of the territory, straddle national borders.

I shall proceed to consider these in the order in which I have designated them.

I. Judicial Responses to a Boundary Delimitation Which Involves Dismantling or Dividing an Ecologically or Culturally Integral Unit

86. The fact that a unique natural preserve, or a treasured cultural site, or a sacred area which needs to be preserved in its full integrity, straddles [p1182] national boundaries does not necessarily mean that it is to be dissected between the two or more States whose boundary runs through it. International law would have resources enough to handle this difficult and delicate situation so as to preserve as a unity the valuable asset which would otherwise suffer from being divided in a manner that takes into account only the rights of individual States, but neglects other values which international law is bound to preserve.

For the large numbers of elephants, hippopotami, and rhinoceroses, not to speak of smaller forms of wildlife, which frequent this area and have been doing so as long as human memory extends, a disturbance of their patterns of occupation would be a disturbance of their natural habitat. The adverse consequences to their well-being and to their survival cannot be underestimated. In a world which increasingly places a strain on their natural lifestyles and habitats, and in which several important categories of wildlife are becoming endangered species, this is a result which is to be prevented as far as such action is permissible within the limits of the law.
87. I refer in particular to the Biodiversity Convention (1992), a Convention which both Botswana and Namibia have ratified without qualification (Botswana, 12 October 1995, and Namibia, 16 May 1997).

The States parties to that Convention have accepted responsibility for conserving their biological diversity and for using their biological resources in a sustainable manner. The Convention notes further that one of the fundamental requirements for the conservation of biological diversity is in situ conservation, defined as "the conservation of ecosystems and natural habitats and the maintenance ... of viable populations of species in their natural surroundings"FN58. It further stresses the importance of and the need to promote international co-operation among States for the conservation of biological diversityFN59.

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FN58 Biodiversity Convention, Preamble, para. 10; ibid., Art. 2. Ibid.,
FN59 Preamble, para. 14.
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88. Article 6 requires each contracting party to develop national strategies, plans or programmes for the conservation and sustainable use of biological diversity. Article 8 (d), dealing with in situ conservation, requires, inter alia, that each contracting party promote the protection of ecosystems, natural habitats, and the maintenance of viable populations of species in natural surroundings. All of these are indicative of the cardinal importance attached by modern international law to the protection of natural species in their natural environments.

So strong are the obligations imposed by the Convention that Article 22 provides that the provisions of the Convention shall not affect the rights and obligations of contracting parties, deriving from any existing international agreement "except where the exercise of those rights [p1183] and obligations would cause a serious damage or threat to biological diversity". This indicates that a serious threat to biological diversity can even constitute an exception to treaty obligations.

I cite these provisions in order to show that specific State obligations exist to protect the natural habitats of wildlife, and that those obligations can even, in certain situations, override existing treaty obligations. The obligations imposed by the Convention are thus of such a compelling nature that they cannot be ignored in any determination defining inter-State rights and obligations if such determination should entail a risk of damage to ecosystems which it was the object of the Convention to prevent.

89. We are here not importing principles of modern law to interpret a treaty of 1890. We are interpreting the Treaty of 1890 as it stood, and as it was understood contemporaneously. We are determining the boundaries between the two States in terms of the Treaty of 1890 but, in applying them on the ground in the year 1999, we cannot disregard important principles of modern law.

Environmental standards transcend temporal barriers, as this Court noted when in Gabcikovo it observed:
"Such new norms have to be taken into consideration, and such new standards given proper weight, not only when States contemplate new activities but also when continuing with activities begun in the past."FN60

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FN60 Gubcikovo-Nagymaros Project, I.C.J. Reports ‘997, p. 78, para. 140.
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Consequently, in environmental matters, today's standards attach themselves to yesterday's transactions, and must be given due effect in judicial determinations stemming from them.

This aspect can be formulated even more strongly in the present case, because the question referred to the Court requires a determination in accordance with "the rules and principles of international law", and also because the Court is obliged to take into account the environmental obligations assumed by the Parties through multilateral treaties.

90. Moreover, this is a court not only of strict law, but of equity as well, and boundary delimitations, like all other determinations of the Court, involve not merely strictly legal but equitable considerations as well. This is not new jurisprudence, but has been recognized as far back as the North Sea Continental Shelf cases61 which noted the relevance of equitable principles in the process of delimitation.

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FN61 I.C.J. Reports 1969, pp. 48-53.
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[p1184 ]

2. The Scope for Equity in Boundary Delimitation

91. A court reaching such a conclusion as that Kasikili/Sedudu Island belongs to Namibia cannot end its responsibilities with the mechanical exercise of a geometric delineation of boundaries on the ground.

I have already advanced the illustration of a sacred site which is one and entire, but which may need to be divided in two if merely geometrical considerations are to be followed. Likewise, a village may be separated from a grazing ground which for centuries had been integral to it, or the village itself may be divided into two parts whose residents thus became citizens of two different States, however closely they may be connected. It would be a diminution of a court's inherent jurisdiction if it were expected in such hypothetical circumstances to turn its glance away from these very real and vital problems and proceed with the task of delineation as if it were a purely geometrical exercise. Charged as it is with the application of equity to the problem before it, a court would not proceed in this fashion.

If there is a natural reserve which, in the interests of the ecosystem and of biological diversity cannot be divided without lasting damage, this is a factor which the Court can no less ignore than a sacred site or archaeological preserve which must be maintained in its integrity if it is to be preserved.

92. There is more than one way in which equitable considerations can be given effect in such situations.

One is that the Court should consider itself empowered to make a slight deviation from the strict geometric path indicated by the boundary treaty, but always preserving a balance between the entitlements of the two parties to the enjoyment of this precious asset.
Another is to constitute, in the larger interests of both parties and indeed of the world community, a joint regime over the area so that neither party is deprived of its use. In this category, a multitude of possibilities and precedents are available which I shall briefly consider later.

93. I may observe here that the division of a sacred site or ecological preserve into two discrete portions is a procedure likely to produce tension between the Parties in the future, as that which was considered to be a common resource on both sides of the border is then available to neither Party, and the entire asset is under risk of destruction through the process of division. Indeed, in an extreme case, as where a geometrical line of partition passes through the most holy place of a sacred site, the imperative need for such discretion on the part of the Court is obvious.

That the Court has such a power, and indeed a duty in an extreme [p1185] case, is thus beyond dispute. Whether a given situation is an appropriate one for the use of its equitable power is a matter for the Court's discretion.

In the present state of recognition of the importance of ecological considerations, and having regard to the importance of this natural reserve as stressed to us by both Parties at the oral hearings, a decision in favour of Namibia would trigger the exercise of such discretion.

3. Treaties Dealing with Spheres of Influence Distinguished from Treaties Dealing with State Boundaries

94. Of special relevance to the exercise of the Court's equitable powers is the distinction which I believe should be drawn between treaties that specifically and precisely deal with boundaries and treaties which deal with spheres of influence.

The distinction I draw is in relation to the degrees of specificity of the two kinds of treaties. In the colonial past, the colonizing powers would sometimes in broad terms define their respective spheres of influence. It was of course necessary to establish the lines of division between them, but the primary purpose of the exercise was to make clear the broad extents of territory over which one or the other could pursue their activities without interference by the other. As Oppenheim has observed, they arose from "the uncertainty of the extent of an occupation, and the tendency of colonizing states to extend an occupation constantly and gradually into the interior or 'hinterland' of an occupied territory"FN62. They had

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FN62 Oppenheim's International Law, Vol. I, Peace, Parts 2 to 4, Sir Robert Jennings andSir Arthur Watts (eds.), 9th ed., 1992, p. 691.
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"the object of regulating, in a spirit of mutual good-will, the relations which might result between the contracting Powers from the extension of their rights of sovereignty or protectorate in neighbouring regions"FN63.

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FN63 M. F. Lindley, The Acquisition and Government of Backward Territory in International Law, 1926, p. 210; see also Sir Thomas Holdich, Political Frontiers and Boundary Making, 1916, pp. 96-97.
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95. These agreements were arrangements with "a certain provisionality", and when in due course the parties took control of the areas respectively reserved, the delimitation would attain the status of a boundary descriptionFN64. Thus a sphere of influence did not necessarily mean that the power claiming it already had control and possession of it, but this was clearly the objective towards which it intended to move.

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FN64 Ian Brownlie. African Boundaries: A Legal and Diplomatic Encyclopaedia, op. cit.. pp. 8-9.
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[p1186]
It has also been observed that "[t]he term 'Sphere of Influence' is one to which no very definite meaning is as yet attached"FN65, and "rather implies a moral claim than a true right"FN66.

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FN65 W. E. Hall, A Treatise on International Law, 8th ed., A. P. Higgins (ed.), 1924, p. 153, para. 386.
FN66 Ibid., p. 154, para. 386.
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There are thus certain elements of provisionality and lack of precise definition associated with the concept, which can assume some relevance where, in a later interpretation of the Treaty, a question of uncertainty regarding the exact definition of a boundary needs to be resolved.

96. As a background to this Treaty and the concept of colonial expansion, it is not irrelevant to note the significant changes effected under Chancellor von Caprivi (after whom the Caprivi Strip is named) in the foreign and colonial policies of Bismarck, whom he succeeded in 1890, the very year of the TreatyFN67. Bismarck had followed a policy of placing little value on colonial expansionFN68, but Caprivi took the line that now that the acquisition of colonies had been started, one could not very well turn backFN69. Indeed, Count Hatzfeldt, who was engaged in negotiating the Treaty in London with Lord Salisbury, is recorded as having observed that he was "impressed with the importance to the two countries of a general settlement on a broad basis which would appease and avert the jealousies and rivalries now unfortunately existing"FN70. Such was the background to the 1890 TreatyFN71, which was thus rather different in its objective from the precise delineation of colonial boundaries aimed at by a treaty dealing strictly with territorial boundaries.

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FN67"For better or for worse, from now [1890] on the Caprivi era would be known as the 'new course'" (J. A. Nichols, Germany after Bismarck: The Caprivi Era 1890-1894, 1958, p. 68).
FN68 See Donald Kagan, On the Origins of War and the Preservation of Peace, 1995, p. 110. For a discussion of the changes in foreign policy and their impact on colonial policy, see ibid., pp. 121 et seq.
FN69 Nichols, op. tit., p. 102, quoting Caprivi's speech during his first appearance in the Reichstag on 12 May 1890. a speech in which he disclaimed being himself a "colonial enthusiast".
FN70 Emphasis added. Memorial of Botswana, Vol. II, Annex 9, p. 51 (Correspondence respecting the Negotiations between Great Britain and Germany relating to Africa, April to December 1890, No. 1).
FN71 The 1890 Treaty with Great Britain was signed simultaneously with the lapsing of the Reinsurance Treaty with Russia, a cornerstone of Bismarck's foreign policy. The 1890 Treaty evidenced the increased interest in the building up of colonial possessions. The policy of clarifying spheres of influence with Great Britain was a natural preliminary stage of this process, so far as Southern Africa was concerned.
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97. Another aspect of the generality of this Treaty is that it covered not merely the territories of the two Parties to the present dispute, but dealt with the spheres of influence of Germany and Great Britain in East Africa (Art. I), South West Africa (Art. III), and West Africa (Art. IV), in addition to other matters dealing with specific designated territories,[p1187] such as the transfer by Britain to Germany of sovereignty over Heligoland. It was thus far more general in its nature than a specifically boundary-oriented treatyFN72, which laid down the exact borders between two States.

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FN72 See further A. J. P. Taylor, Germany's First Bid for Colonies: 1884-1885, 1938, p. 98.
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98. The emphasis, therefore, was on areas of interest rather than linear boundaries. A major difference between boundary treaties, stricto sensu, and zones of influence treaties is that zones of influence treaties deal with spatial zones while boundary treaties involve points or lines that have no breadthFN73. Consequently, there is a precision and definiteness attending a boundary treaty which distinguishes it from the generalized nature of a treaty dealing with spheres of influence. In the expressive language of Brownlie, a boundary treaty "draws precision and clarity in its train"FN74. The same cannot be said for spheres of influence treaties.

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FN73 Brownlie, op. cit., p. 3.
FN74 Ibid.
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This is not a conclusive factor in the present case, but is not without its implications in the particular circumstances here, for

(a) it gives the Court greater flexibility in the definition of the boundary in question, while of course not departing from the terms of the Treaty;

(b) it gives the Court greater scope for the application of equitable principles;

(c) it widens the latitude available to the Court for making provision for the integrity and preservation of important features such as environmental preserves; and

(d) it enables the Court to take into account such factors as that one interpretation will draw a line between a given people and the land which they have traditionally used over a long period of time, while the other will not, thereby inclining the Court towards the former interpretation, if it be possible within the terms of the Treaty.

99. In the present case, this factor makes easier the resolution in favour of Namibia of the doubt regarding interpretation. It would also incline the Court against a formalistic interpretation which deprives a people of land which they have used over the generations without any acknowledgment of any other sovereignty over it and without any assertion of right by the State claiming such sovereignty. A zones of influence treaty would permit more flexibility in this regard than a treaty dealing strictly with boundaries. [p1188]

To attach the Island which the Masubia had long regarded and used as theirs to another sovereign State upon a literal interpretation of a zones of influence treaty would perhaps represent an overly formalistic approach to an essentially human problem.

100. At the same time, the additional leeway resulting from this fact would make it easier for the Court, in holding with Namibia, to make appropriate provision in its Order for preserving in its integrity as one comprehensive whole the wildlife habitat which comprises both the Island and the Chobe Game Park to the south. The Court would be able to exercise its equitable powers to require Namibia to enter into a joint regime with Botswana in order to ensure the integrity of this habitat.

101. The fact that the Treaty under interpretation was one demarcating zones of influence, and not a boundary treaty, is thus not without significance in the present case.

Needless to say, nothing in this opinion affects the principle of' uti possidetis juris, for the task we are engaged on is that of defining the boundary in terms of the Treaty of 1890, as interpreted according to the legal principles applicable.

4. Joint International Regimes

102. The notion of joint regimes in areas straddling national boundaries has grown remarkably in recent years. There is thus a plenitude of models and ideas from which to draw the appropriate principles for the fashioning of a co-operative international regime that suits a particular case.

I cite initially an observation in the Foreword to a recent work on International Boundaries and Environmental Security: Frameworks for Regional Cooperation, to the effect that:

"Modern boundary-making theory emphasises the virtue of flexibility at least as much as the traditional virtues of certainty and finality . . . but increasingly, in the case of ocean and river boundary contexts, . . . boundary-makers might be wiser to regard themselves less as the drawers of lines than as the designers of workable regimes."FN75

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FN75 Gerald Blake el at. (eds.), 1997, pp. xi-xii.
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103. The Court is not, of course, a boundary-maker, but the entity charged with translating the terms of a treaty into conditions on the ground, adhering as faithfully to the Treaty as it can in accordance with international law. Since modern international law dictates a regard for [p1189] certain environmental considerations, this aspect must be taken into account in interpreting and applying the Treaty, with due regard to current legal concepts and standards. Of these current concepts, the concept of a joint regime over a resource which is valuable to both parties must receive judicial attention as a rapidly developing concept of international law.

104. Instances are not wanting of judicial recognition of the need to prevent a merely mechanistic division which takes no account of human factors and practical realities. In Frontier DisputeFN76, the Chamber gave its careful consideration to a situation in which certain villages had appurtenant to them certain farming hamlets which were situated some distance away from them. The village was the native administrative unit and comprised all the land dependent on it. Mali argued specifically that the land dependent on a village included the farming hamlets. A line drawn between the village and the agricultural/grazing site could destroy the unity that had always existed between them. The Chamber showed its sensitivity to this issue, but was not called upon in that case to make a decision on this matter, as "[f]rom a practical point of view, the existence of such rights has posed no major problems"FN77, but it nevertheless observed that:

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FN76 Frontier Dispute (Burkina Faso/Republic of Mali), I.C.J. Reports 1986, p. 554.
FN77 Ibid., p. 617, para. 116.
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"In this matter, it all depends on the circumstances. The Chamber considers . . . that it will be able to ascertain whether a particular piece of land is to be treated as part of that village despite its lack of a connection with it, or as a satellite hamlet which does not fall within the boundaries of the village in the strict sense."FN78

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FN78 Ibid, para. 117.
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105. In the same case, the notions of flexibility and the role of equity in demarcating the boundaries arose also in relation to a frontier pool. The Chamber there explained that it could resort to equity infra legem on the basis of the guiding concept that "Equity as a legal concept is a direct emanation of the idea of justice"FN79, but that equity could not be used to modify an established frontier in the sense of a settled border. Acting on that basis, the Chamber resorted to equitable considerations in determining how the frontier pool should be divided.

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FN79 Ibid., para. 149, quoting Continental Shelf ( Tunisia! Libyan Arab Jamahiriya), I.C.J. Reports 1982, p. 60, para. 71.
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106. In the present case, there is no established frontier in the sense of a settled boundary. Rather, the Court is in the process of settling that [p1190] boundary in accordance with the 1890 Treaty. In settling that boundary in accordance with the law, it is entitled to take equitable considerations into account so long as it does not depart from the terms of the Treaty. The equitable consideration of preserving this valuable natural resource in accordance with governing principles of environmental law does not in any way militate against the basic adherence to the terms of that Treaty which lies at the root of my conclusions.

107. We here have a situation of one of the world's richest wildlife reserves falling within the territory of Namibia, if my interpretation of the 1890 Treaty be correct. However, there can be no doubt that the rich wildlife moves over to the Island from the south and that the Island and the land to the south of it, which latter is in Botswanan territory, together form one integral natural preserve. Since merely drawing national boundaries between them so as to divide this resource in two would destroy its unique nature and affect its unique value for all time, something more is called for in such a situation. The establishment of a joint regime, in cases where it is appropriate, would be one of the equitable bases on which the Court could proceed in cases where such a regime would be appropriate to govern the situation resulting from the Court's determination.

108. The notion of joint regimes received recognition from this Court in the North Sea Continental Shelf casesFN80. The Court there indicated a number of factors to be taken into account in the negotiations between the parties. The separate opinion of Judge Jessup, recalling other instances of international co-operation, observes that "the principle of international co-operation in the exploitation of a natural resource is well established in other international practice"FN81.

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FN80 I.C.J. Reports 1969, pp. 53-54.
FN81 Ibid., p. 82.
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In such a joint regime, the authorities of both countries acting together would, in the best interests of the preservation of this valuable resource, follow certain mutually agreed guidelines which accord with the principles of international environmental law applicable to such a resource.

109. International experience, covering numerous aspects of joint regimes, is accumulating in many parts of the world. For example, the La Paz Agreement of 1983, the Great Lakes Water Quality Accord of 1978, and the North American Free Trade Agreement of 1992 have stimulated developments in this area in North America. The Environmental Side Agreements of NAFTA have resulted in a series of new international institutions and a more comprehensive approach to regional and environmental issuesFN82. In the Asian region, Cambodia, Thailand, Laos and Vietnam have made elaborate arrangements for the development of the [p1191] Mekong RiverFN83. In Eastern Europe the Gabcikovo-Nagymaros case highlighted the importance of bilateral arrangements within the framework of mutually acceptable guidelinesFN84. In the Mediterranean area, there has been a growing volume of State co-operation since the Barcelona Convention was signed in 1976FN85.

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FN82 Blake, op. cit., p. 249.
FN83 Statute for Co-ordination of Investigation of the Lower Mekong Basin, 1957, supplemented in 1995 in much detail by the Agreement on Co-operation for the Sustain-able Development of the Mekong River Basin, setting out a regime for even closer co-operation in regard to irrigation, hydropower, flood control, fisheries, timber floating, recreation and tourism, governed by the Mekong River Commission; see also, GeraldBlake, op. cit., p. 294.
FN84 I.C.J. Reports 1997, pp. 78-79, paras. 140-144.
FN85 See the Protocol on Specially Protected Areas to the Barcelona Convention for theProtection of the Mediterranean Sea against Pollution (1982) by which signatories pledged to improve the state of natural resources and natural sites in the Mediterranean Sea byestablishing and managing protected areas in the region.
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On the basis of the Mediterranean experience, the United Nations Environmental Programme has sponsored several other "Regional Seas" conventions in various parts of the world.

A legal framework for co-operation is contained in the 1982 United Nations Convention on the Law of the Sea, Article 123 of which obliges States bordering enclosed or semi-enclosed seas to co-operate with each other, inter alia, over environmental protection.

Joint management regimes have been established for the integrated development of resources in river basins with States splitting costs and responsibilities and sacrificing sovereignty as needed to facilitate the management process. Many agreements have been worked out for the joint management of continental shelf areas, and some with many specific provisions relating to protection of the marine environment and its flora and fauna.

There is thus much movement in the direction of international cooperation to protect the environmentFN86, and the time is opportune for models to be evolved for such co-operative administration of environmentally important areas of special significance.

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FN86 For the vast variety of approaches to this problem, classified under scientific responses, economic responses, institutional responses, moral responses, and legal implementation, see Lakshman D. Guruswamy and Jeffrey A. McNeely (eds.), Protection of Global Biodiversity: Converging Strategies, 1998.
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[p1192]
110. Outside the environmental area, many joint management rιgimes straddling national boundaries have been worked out, and have functioned successfully.

Their experience of joint management rιgimes and joint use regions can also be harnessed in the environmental field.

Bilateral and multilateral arrangements have laid down many principles regarding the sharing of resources, joint administration, and rights of mineral exploration over another State's sovereign territory. Such agreements contain many examples of the prohibition, despite national sovereignty over the region, of certain types of operations. Among these are such varied examples as oil drilling and the construction of fortifications within designated areas.

Precedents prohibiting certain types of activity in the zone in questionFN87 could also be particularly useful where environmental protection is concerned.

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FN87 For example. Agreement concerning the Sovereignty over the Islands of Al-'Arabi-yah and Farsi, and the Delimitation of the Boundary Line Separating the Submarine Areas between the Kingdom of Saudi Arabia and Iran (1968), prohibiting oil drilling operations within 500 m of the boundary on either side. See, also. Treaty between the Hungarian People's Republic and the Republic of Austria concerning the Regulation of Water Economy Questions in the Frontier Region (1956). This agreement prohibits a State from planning or constructing hydraulic works in the frontier waters of its own territory without consulting the other State, and prohibits any effect that would decrease the supply of water to the other State. It established the Permanent Hungarian-Austrian Water Commission to oversee any planning and settle disputes.
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Other agreements create a geographic zone straddling the boundary, allowing for joint exploration and exploitation of resourcesFN88. Petroleum developmentFN89, river managementFN90, fishing rightsFN91, transit passageFN92, [p1193] water and hydropowerFN93, pilgrimageFN94, irrigationFN95, and the use of arable and pasture landsFN96 are some areas in which co-operative arrangements have been made, some of them dating back to periods long before environmental considerations had become a major issue.

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FN88 For example, Convention between the Government of the French Republic and the Government of the Spanish State on the Delimitation of the Continental Shelves of the Two States in the Bay of Biscay (1974).
FN89 For example. Agreement on Settlement of Maritime Boundary Lines and Sovereign Rights over Islands between Qatar and Abu Dhabi (1969), providing for equal rights of ownership and revenue sharing with respect to an oil field through which the boundary runs.
FN90 For example, Itaipu Treaty (1972) between Brazil and Paraguay by which the section of the river that borders the two countries is owned and closely managed and monitored by the respective Governments.
FN91 For example. Agreement between the Kingdom of Sweden and the Union of Soviet Socialist Republics on the Delimitation of the Continental Shelf of the Swedish Fishing Zone and the Soviet Economic Zone in the Baltic Sea (1988), providing that, in the formerly disputed area, each party will have fishing rights in that part of the zone allocated to the other party.
FN92 For example, Treaty between the Republic of Trinidad and Tobago, and the Republic of Venezuela on the Delimitation of Marine and Submarine Areas (1990) by which Venezuelan ships and aircraft were granted the rights of transit passage through the strait located between Trinidad and Tobago.
FN93 For example, Convention between the French Republic and the Federal Republic of Germany concerning the Development of the Rhine between Strasbourg/Kehl and Lau-terbourg/Newburgweier (1969); Treaty between the United States and Canada Relating to Co-operative Development of Water Resources Relating to the Columbia River Basin(1961); Agreement between Argentina and Uruguay Relating to the Utilization of the Rapids of the Uruguay River in the Area of Salto Grande (1946).
FN94 For example, Agreement between India and Sri Lanka on the Boundary in Historic Waters between the Two Countries and Related Matters (1974).
FN95 For example, Treaty between Chile and Peru for the Settlement of the Dispute Regarding Tacna and Arica (1929), by which Chile gave Peru an easement over sections of certain irrigation channels which pass through Chilean territory.
FN96 For example, Exchanges of Notes between the United Kingdom and France Constituting an Agreement Relating to the Boundary between the Gold Coast and French Sudan (1904) by which villages situated in proximity to the frontier shall enjoy rights to the use of arable and pasture lands, springs, and watering places on the other side of the border. Similar clauses were contained in agreements relating to the boundary between the Gold Coast and Ivory Coast (1905), and Southern Nigeria and Dahomey (1906).
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The precedents are growing and the areas of co-operation expanding. The environmental area is one which is being particularly developed.

111. Many of these agreements include the establishment of a Joint Technical Commission or other co-operative supervisory body as well as a co-ordinate Declaration signed by the two Governments concerned, setting out a statement of principles which they will follow in the conservation or utilization of this common resourceFN97. A notable instance of such joint regulation is the Frontier Water Commission and the Supreme Frontier Water Commission created by Germany and Denmark in the very detailed arrangement for the management of six watercourses between Germany and Denmark, under the 1922 Agreement between Denmark and Germany Relating to Watercourses on the German-Danish FrontierFN98.

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FN97 For both of these, see the Uruguay River Agreement referred to above. This Agreement was supplemented by the Declaration on Water Resources (1971) signed by the two Governments calling for the equitable and reasonable utilization of the river's water resources, and the prevention of pollution.
FN98 For another example of detailed joint management provisions, see the Treaty between the Kingdom of the Netherlands and the Federal Republic of Germany concerning the Course of the Common Frontier, the Boundary Waters, Real Property Situated Near the Frontier, Traffic Crossing the Frontier on Land and via Waters, and Other Frontier Questions (1960), which creates a Permanent Boundary Water Commission, sub-commissions, and an arbitral tribunal to co-ordinate management and settle disputes.
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112. The international community has expressed concern for many years regarding the protection of environmental resources shared by two [p1194] or more States, and I refer in this connection to General Assembly resolution 3129 of 13 December 1973 on Co-operation in the Field of the Environment concerning Natural Resources Shared by Two or More States, which stresses the necessity to ensure effective co-operation between countries for the conservation of natural resources common to two or more States. A similar concern for co-operation, in relation to transboundary environmental problems, was shown in Article 5 of the Ramsar Convention.

It would be in the spirit of resolutions such as this that such a joint regime be co-operatively evolved and brought into operation. The principles of environmental protection which they seek to foster have passed beyond the realm of mere aspiration, and are now part of customary international law.

113. I should refer also to the growing concern on the African continent for the preservation of valuable flora and fauna resources, as evidenced through such instruments as the African Convention on the Conservation of Nature and Natural Resources (the Algiers Convention) of 1968, by which 29 African States agreed to ensure, inter alia, the conservation, utilization, and development, in accordance with scientific principles, of flora and fauna resources, listing for this purpose a wide variety of protected species. It also requires the creation by participating States of conservation areas.

Conclusion

114. With these precedents and principles before them, there is ample scope for the Parties to be required to work out a joint regime for such matters as:

(a) protection of flora and fauna;

(b) right of access to the Island for citizens of both States;

(c) regulation of tourist traffic;

(d) river management and conservation;

(e) licensing of river craft;

(f) freedom of movement of wildlife to and from the Island;

( g) supervision by game wardens;

(h) permitted and prohibited activities on the Island;

(i) the adoption of a common set of principles for the protection of the natural resources of the area, including in particular the care and custody of wildlife.

In the event of a dispute regarding such administrative framework, the Court's assistance would always be available to the Parties, if so desired.

115. It is useful to note also in this regard the statement made to the Court by Namibia regarding its willingness to undertake joint anti-poaching measures with Botswana. In Namibia's submission: [p1195]

"Apart from our commitment to conservation, we believe that such joint anti-poaching measures would greatly enhance mutual trust and co-operation between the people of Namibia and Botswana."FN99

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FN99 CR 99/10, p. 16, para. 24.
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116. I would therefore hold that, while Kasikili/Sedudu Island falls within the sovereignty of Namibia, Namibia is obliged to negotiate with Botswana towards a mutually acceptable joint regulatory rιgime regarding, inter alia, the matters set out above. Such action must be within the framework of principles set out in the Biodiversity and other Conventions to which both States are parties. Until such time as the Joint Regulatory Rιgime is set up, the game wardens and tourists of Botswana shall have access to the Island.

***

117. The future will demand an international law that is sensitive and responsive to the problems of environmental law. The careful integration of the necessary principles of environmental law into the traditional body of international law is an important task awaiting attention. The prin-ciples and the duties arising from environmental obligations now superimpose themselves upon such rights arising from State sovereignty as may have been recognized by prior international law in an absolutist form.

118. The dispute here under consideration offers an opportunity for significant movement in this direction, with the possibility it presents for the incorporation of environmental concerns into boundary delimitation, and with the development of the concept of joint regimes for conserving the common environmental heritage. As international law reaches out to face the problems of the future, considerations of co-operative action may well seem appropriate where undiluted considerations of individual sovereignty once held sway.

119.1 would like to observe in conclusion that the pressures bearing down on the environment are so universal that the international disputes of the future will increasingly involve considerations of an environmental nature. These considerations, if not directly or indirectly related to the matters in issue, will often be at least peripheral to them. Judicial decisions will necessarily be obliged to take them into account. International law will not be without its resources of evolving concepts and mechanisms wherewith to address these unprecedented concerns.

(Signed) Christopher G. Weeramantry. [p1196]


DISSENTING OPINION OF JUDGE FLEISCHHAUER

I have voted against paragraphs 1 and 2 of the dispositif of the Court's Judgment. For the reasons which I will explain below, I dissent from the Court's interpretation of the term the "main channel of that river"/ "Hauptlauf dieses Flusses"FN1 in Article III (2) of the 1890 Treaty as meaning the northern rather than the southern channel of the Chobe around Kasikili/Sedudu Island. As for the rest of the Judgment, I agree with almost all its other parts, including the conclusion that the rules reflected in Article 31 of the Vienna Convention are applicable to the interpretation of the 1890 Treaty and the finding that the boundary established by Article III (2) of that Treaty follows the thalweg rather than the median line of the main channel. As the Court does not accept Namibia's argument on acquisitive prescription, the territorial status of the Island depends entirely on the course of the boundary. My dissent on the interpretation of the term "main channel of that river"/"Hauptlauf dieses Flusses" therefore affects not only my view on the location of the boundary, but also my view on the status of the Island. This explains why I voted not only against the first but also against the second paragraph of the dispositif. For considerations which I will also explain below, I voted, however, in favour of the third paragraph.

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FN1 In Article III (2) of the 1890 Treaty the term is used in the genitive. That makes it read in German des Hauptlaufes dieses Flusses. For reasons of convenience, I quote the term in German in the nominative Hauptlauf dieses Flusses.
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Among the many parts of the Judgment with which I agree, is the Court's conclusion that Namibia has no title to the Island based on prescription, as

"Namibia has not established with the necessary degree of precision and certainty that acts of State authority capable of providing alternative justification for prescriptive title, in accordance with the conditions set out by Namibia, were carried out by its predecessors or by itself with regard to Kasikili/Sedudu Island" (Judgment, para. 99). [p1197]

But, in my view, the Court should also have found that Namibia's immediate predecessor in the Caprivi Strip, South Africa, could not have acquired prescriptive title over the Island.

My reasoning is as follows:

I. The Interpretation of the Term "Main Channel"/"Hauptlauf" in Article III (2) of the 1890 Treaty

The Applicable Law

1. The Judgment correctly starts from the fact that although

"neither Botswana nor Namibia are parties to the Vienna Convention on the Law of Treaties of 23 May 1969, . . . both of them consider that Article 31 of the Vienna Convention is applicable inasmuch as it reflects customary international law" (Judgment, para. 18).

The Judgment goes on to say that "[t]he Court itself has already had occasion in the past to hold that customary international law found expression in Article 31 of the Vienna Convention" (ibid.); it further says

"Article 4 of the Convention, which provides that it 'applies only to treaties which are concluded by States after the entry into force of the . . . Convention . . .' does not, therefore, prevent the Court from interpreting the 1890 Treaty in accordance with the rules reflected in Article 31 of the Convention." (Ibid.)

2. The Vienna Convention on the Law of Treaties establishes in its Articles 31-33 a system of treaty interpretation. Article 31, paragraph 1, provides that, based on the principle of good faith, the ordinary meaning of the term to be interpreted has to be explored in the light of the object and purpose of the treaty in which the term finds itself and the context in which it is used. While upholding that the parties are to be presumed to have that intention, which appears from the terms used by them, the Vienna Convention thus does not force the Court to find the abstract meaning of contested terms and to proceed on that basis; what the Court is asked is rather to explore the intention of the Parties, the reason why they used the particular term, and to proceed on that more nuanced basis.

The Ordinary Meaning of the Term "the Main Channel of That River"/”Hauptlauf dieses Flusses"

3. Looking at the term as used in Article III (2) of the 1890 Treaty, I note that in its ordinary meaning it does not give an even approximately precise indication of the channel of the Chobe River in which the delimit-[p1198] tation between the British and the German spheres of interest is to be placed. It seems that the negotiating parties had, through reports of travellers and explorers and early maps prepared by them, a superficial knowledge of the topography they were dealing with (see Benjamin Brad-shaw, "Notes on the Chobe River, South Central Africa", Proceedings of the Royal Geographic Society (1881), pp. 208 ff., Memorial of Namibia, Vol. V, Ann. 115, pp. 117 ff.; Map 1/2, ibid., Vol. VII, p. 4). The reference to the "main channel of that river"/"Hauptlauf dieses Flusses" indicates that they knew that the Chobe has, at different locations at least, several channels, and that they wanted to place the line of delimitation into the principal one of these channels. But there the matter ends. There is neither in English nor in German a common understanding of the term which would apply in a general fashion to the determination, in case of doubt, which among several channels of a river is the main one. There is — as the discussion about the role of navigability in the determination of the main channel of the Chobe shows — not even agreement on all of the criteria which play a role for that evaluation and disagreement on the meaning or weight to be given to some of them. And the same is true for the German word "Hauptlauf.

Nor is there an ordinary meaning of the term "main channel of that river"/"Hauptlauf dieses Flusses" in a hydrological sense. The intense hydrological debate which has taken place for years between the Parties and during these proceedings before the Court, was about, inter alia, the annual flow of water that goes through either of the two channels and in this context about what precisely constitutes the southern channel, the comparative visibility of the two channels during the flow seasons and during the dry parts of the year and the bed profile configuration of the channels. The Parties did not only disagree in substance on these matters, but also on their relevance and applicability in the determination of the main channel of the Chobe at Kasikili/Sedudu Island.

4. The Judgment lays much weight on the ordinary meaning of the term "main channel of that river''/"Hauptlauf dieses Flusses". In order to define that meaning, the Court bases itself on "the most commonly used criteria in international law and practice, to which the Parties have referred" (Judgment, para. 27).

Accordingly, the Court addresses the criteria relied on by the Parties and analyses their views on each of them before formulating brief conclusions of its own (Judgment, paras. 29-41). As a result, the Court is no more successful in establishing the ordinary meaning of "main channel of that river"/"Hauptlauf dieses Flusses" than the Parties are in their parallel efforts. A number of the conclusions arrived at by the Court are not arbitrary as they are based on presentations by the Parties, but nevertheless subjective in nature and without a clear justification. In the end the Court's conclusion that [p1199]

"in accordance with the ordinary meaning of the terms that appear in the pertinent provision of the 1890 Treaty, the northern channel of the River Chobe around Kasikili/Sedudu Island must be regarded as its main channel" (Judgment, para. 41)

remains unconvincing.

Apparently recognizing the shortcomings of its efforts, the Court repeatedly refers to the findings of Captain Eason in 1912, Messrs. Trol-lope and Redman in 1948, and the Joint Survey of 1985, all of which are to the effect that, at Kasikili/Sedudu Island, the northern channel of the Chobe has to be regarded as the "main channel of that river"/"Hauptlauf dieses Flusses" (Judgment para. 33, para. 42, and para. 80). The Judgment correctly states that those findings do not constitute subsequent agreements or subsequent practice in the sense of Article 31, paragraph 3, but refers to them as giving support to its own conclusion on the northern channel as the main channel of the Chobe around Kasikili/Sedudu Island:

"The Court finds that these facts, while not constituting subsequent practice by the parties in the interpretation of the 1890 Treaty, nevertheless support the conclusions which it has reached by interpreting Article III, paragraph 2, of the 1890 Treaty in accordance with the ordinary meaning to be given to its terms . . ." (Judgment, para. 80.)

In making this statement however, the Court does not take account of the fact that neither Eason nor Trollope and Redman were hydrological experts and that the Court has not been informed of the basis on which they reached their conclusions; moreover, the report on the Joint Survey, according to South Africa, did not prove conclusively that the Island belongs to Botswana.

In its effort to establish an ordinary meaning of the term to be interpreted, on which the Court could proceed, the Judgment is not fully consonant with the system of interpretation provided for by the Vienna Convention. It discusses only certain aspects of the object and purpose of the 1890 Treaty and does not deal at all with the context in which the term "main channel of that river'V'Hauptlauf dieses Flusses" is used in that Treaty (Judgment, paras. 43-45). Object and purpose of the Treaty in which the term to be interpreted finds itself and the context in which the term has been used, are important elements of treaty interpretation as they throw light on the intentions of the Parties which are a key factor for treaty interpretation as foreseen by the Vienna Convention. An interpretation of the term "main channel of that river"/"Hauptlauf dieses Flusses", which properly takes into account the object and purpose of the Treaty and the context in which this term is used in Article III (2), leads to a result that is different from the one reached by the Court in its Judgment. [p1200]

Object and Purpose of the 1890 Treaty

5. As to object and purpose of the 1890 Treaty, I would like to first observe that the 1890 Treaty is a bilateral treaty and that, as is often the case with bilateral treaties, object and purpose pursued with the Treaty by its parties follow fairly clearly from its text. The object of the 1890 Treaty were the spheres of influence of the two contracting parties in Africa and the purpose was their agreed delimitation (Arts. I-IV of the Treaty) in order to secure the respect by each of the parties of the sphere of the other (Art. VII). Although the delimitations provided for in the Treaty have evolved to become existing boundaries between African States, including the boundary between Namibia and Botswana, the Treaty has not to be regarded as a boundary treaty in the technical sense; the Treaty was meant to keep the political relations between the two contracting States undisturbed by rivalry in Africa. This cannot be overlooked in its interpretation; the Treaty must not be understood as meaning a comprehensive settlement of all questions regarding the actual course of the delimitations it establishes. It seems quite compatible with the Treaty's object and purpose that, in certain places, it sets forth only in broad lines where the delimitation of the spheres of interests runs but leaves the fixation of its course in detail to the future application of the Treaty.

What has just been said on the object and purpose of the 1890 Treaty means what follows for the determination of the meaning of the term "main channel of that river" in Article III (2) of that Treaty.

6. The object and purpose of the 1890 Treaty were that the parties wanted to establish an easily definable delimitation of their zones of influence in the north-eastern corner of South West Africa as well as elsewhere in Africa. Once they had given up the reference to parallels of lati-tude and longitude in the drawing of the line of delimitation, the next best method from the point of view of clarity would have been to fix, in the area of Kasikili/Sedudu Island, the line of delimitation on the crest of the Chobe Ridge. The Chobe Ridge runs on the south bank of the Chobe River, which is the right bank, and was known at the time of the negotiation of the Treaty (see B. F. Bradshaw, "Notes on the Chobe River, South Central Africa", Proceedings of the Royal Geographic Society (1881), pp. 208 ffi). The Ridge is clearly visible and does not disappear under water in the flood season. However, for reasons which have to do with the supposition of the parties that the Chobe is navigable and gives access to the Zambezi by river, the parties to the 1890 Treaty specified that the line of delimitation had to be in the "main channel of that river"/'Hauptlauf dieses Flusses", meaning the Chobe.

This now makes the southern channel the "main channel"/ Hauptlauf in the sense of Article III (2). This is so because in the entire area of Kasikili/Sedudu Island the southern channel runs along the Chobe Ridge. The Chobe Ridge acts like a dam along which the waters of the Chobe run upstream in the beginning of the flood season when they are backed [p1201] up by the Mambova Rapids and downstream at the end of that season. The Ridge also backs up the overflow waters that come down from the Zambezi and directs them to flow off through the southern channel. Consequently the yearly flow of water in the southern channel is such that the Parties disagree whether the northern or the southern channel has the greater flow. The Chobe Ridge also identifies the location of the southern channel and thereby a boundary located in that channel; even in times of high water, when the left bank of the southern channel is under water, the exact location of the thalweg can be established from the Ridge, once the necessary measurements have been taken during the dry season. This could not be easily done in the northern channel, both banks of which are under water in the flood season.

Object and purpose of the 1890 Treaty therefore show that the "main channel"/"Hauptlauf of the Chobe in which the boundary is meant to run is the southern channel.

This finding is supported by the fact that after the conclusion of the 1890 Treaty it was at first generally assumed as quite natural that the delimitation line established by the Treaty lies in the southern channel, an assumption that found its way into early maps.

The Context in Which the Term "Main Channel of That River”/"Hauptlauf dieses Flusses" Is Used in Article III (2) of the 1890 Treaty

7. The context in which the terms of a treaty are used is necessarily connected with the object and purpose of the treaty itself. That does not mean, however, that the context is always identical with, or indistinguishable from, object and purpose of the treaty. The context in which a term is used in a treaty may relate to the overall realization of the object and purpose of the treaty; but the context may as well concern the realization of a particular feature or aspect of the treaty. This is the case with the term "main channel of that river"/"Hauptlauf dieses Flusses" in Article III (2) of the 1890 Treaty.

Article III deals with the spheres of influence of the two contracting parties in South West Africa, and paragraph 2 of this Article in particular with the eastern delimitation of the sphere of influence reserved for Germany. In establishing that delimitation, the two parties intended to meet a particular German request, accepted by Great Britain, namely that "Germany shall have free access from her Protectorate to the Zambesi" (second subparagraph of Article III (2)).

Rivers were regarded at the time as potentially important means for the further exploration and the development of Africa. As the Judgment states: "The great rivers of Africa traditionally offered the colonial [p1202] powers a highway penetrating deep into the African continent." (Judgment, para. 44.) The German interest in access to the Zambezi was motivated by such conceptions. The access of Germany to the Zambezi was to be twofold: by land and by river.

As to the access by land, the second subparagraph of Article III (2) of the 1890 Treaty states that the access of Germany to the Zambezi shall be "by a strip of territory which shall at no point be less than 20 English miles in width". The access by river was to be through the River Chobe and the delimitation between the British and the German sphere of interest was to run in the "centre of the main channel of that river"/" Thalweg des Hauptlaufes dieses Flusses" to "its junction with the Zambesi, where it terminates" (Art. Ill (2) of the 1890 Treaty), so that both parties had equal access to the Chobe and its uses. Originally there was only the reference to access to the Zambezi by the Chobe. The passage regarding access by land did not yet figure in the text initialled by the British and German negotiators on 17 June 1890, 13 days before the signature of the Treaty. Until then, there was only the following reference to the Chobe:

"The frontier between the German territory and the English territory in the south-west of Africa shall follow, from the point which has been agreed upon in previous arrangements, the 22nd degree of south latitude (leaving Lake Ngami to England), to the east up to the 21st degree of longitude; from thence to the north to where that degree touches the 18th degree of south latitude. Thence the line of demarcation shall be carried to the east along the centre of the River Tschobi, up to the point where it flows into the Zambesi." (Initialled Agreement between the representatives of Germany and Great Britain, 17 June 1890 (PRO, FO 881/6146, No. 48), Memorial of Namibia, Vol. IV, Ann. 21, p. 114; emphasis added.)

The negotiating history of the term "main channel of that river"/ "Hauptlauf dieses Flusses" in Article III (2) of the 1890 Treaty thus confirms that this term has been used in the context of an effort to give equal access to the Zambezi by the River Chobe. Navigability therefore is an important factor for the interpretation of the meaning of the term.

8. The context in which the term "the main channel"/"Hauptlauf dieses Flusses" is used in Article III (2) of the Treaty speaks rather in favour of the northern channel as the main channel. In that channel, conditions for navigation seemingly are better than in the southern channel to the degree that the northern channel is, in the dry periods, deeper and wider than the southern channel. That would speak in favour of interpreting the term main channel of "that river"/" Hauptlauf dieses Flusses" as referring to the northern channel.

As a means of interpretation, the context in which the term "main channel of that river"/"Hauptlauf dieses Flusses" is used in Article III (2) of the 1890 Treaty, is therefore at cross purposes with interpretation of [p1203] the term in accordance with object and purpose of the Treaty which indicates the southern channel as the main channel. This contradiction does not however have to be addressed because the expectations of the parties regarding the navigability of the Chobe were mistaken.

The Error of the Parties to the 1890 Treaty in the Appreciation of the Possible Uses of the Chobe River

9. In placing hopes in the expected navigational use of the Chobe River, the parties were in error; the context in which they perceived the "main channel of that river"/"Hauptlauf dieses Flusses" was unreal. We know now, more than hundred years after the conclusion of the Treaty, that the river has not been used, and is not usable, for larger-scale navigation. This is mainly due to the fact that if there was a fully navigable part of the Chobe, it would run from nowhere to nowhere, i.e., from some point upstream from Kasikili/Sedudu Island to the point where — downstream from the Island — the Mambova Rapids block navigation. But also the particular hydrological conditions prevailing in the Chobe in the area around Kasikili/Sedudu Island would not permit full navigational use of the river there. This is supported by the fact that while an attempt at lumber floating was undertaken by Mr. Ker in 1947-1948, the Court has not been informed that this attempt was repeated after Mr. Ker's first experience. The Zambezi Queen is not operated on a regular schedule but is moored in the northern channel as a floating hotel. The only navigational activity which has ever, in a sustained way, been carried out on the River Chobe, is the operation of the tourist flatboats that has taken place, for some time now, mainly in the southern channel, as the Island is becoming known as a major wildlife feeding ground readily accessible to safe viewing by tourists who mainly come from Botswana. The parties to the Treaty were thus in error when they drafted the Treaty in the expectation of larger-scale navigational usability of the Chobe, in particular in giving access to the Zambezi.

The error with which the Court is confronted here is not an error "in a treaty" as dealt with by Article 48 of the Vienna Convention on the Law of Treaties, which one State party to the treaty wishes to invoke "as invalidating its consent to be bound by the treaty". It is rather an error in motivation which led to the use of the term "main channel of that river"/ "Hauptlauf dieses Flusses" in Article III (2) of the 1890 Treaty, an error made by both parties to the Treaty. The question that arises does not concern the validity of the consent to be bound by the Treaty; the error rather raises the question whether a mistaken expectation of the parties when they drew up the Treaty can still serve, more than 100 years after the conclusion of the Treaty and a long time after the error has become clear, in the interpretation of the Treaty.[p1204]

In the circumstances of the present case, the interpretation of the term "main channel"/"Hauptlauf dieses Flusses" based on the mistaken expectation of large-scale navigational usability of the Chobe cannot be held against Namibia because that would mean that Namibia alone would be burdened with the consequences of the error. The flatboat navigation connected to the tourist activities that have evolved on and around Kasikili/Sedudu Island is concentrated in the southern channel. Interpretation of the term "the main channel of that river'"/" Haup lauf dieses Flusses" in favour of the northern channel would deprive Namibia from having an equitable share in the only navigational use of the Chobe there is to share. That would run directly counter to the intention of the parties to split the river evenly. Therefore the interpretation of the term "main channel of that river"/"Hauptlauf dieses Flusses" in favour of the northern channel would not be compatible with the principle of good faith which, according to Article 31, paragraph 1, of the Vienna Convention, governs all treaty interpretation. Interpretation of the term "main channel of that river"/"Hauptlauf dieses Flusses" in favour of the southern channel, however, would correspond to what the parties wanted to achieve regarding the River Chobe. It would be a good faith interpretation of the term because it would split evenly between the Parties the only channel that is of some navigational interest.

Since the Court has found — correctly — that Namibia does not have a prescriptive title to Kasikili/Sedudu Island, the finding that the main channel is the northern channel automatically clarifies that Kasikili/ Sedudu Island is not part of Namibia, but part of Botswana. To arrive at such an important conclusion from the interpretation of a term of the 1890 Treaty based on a mistaken expectation of the navigational usefulness of the Chobe River is equally not compatible with the requirement of good faith in the interpretation of treaties.

In sum, the context in which the term "main channel of that river"/ "Hauptlauf dieses Flusses" is used in Article III (2) of the 1890 Treaty does not justify the interpretation of the term in favour of the northern channel.

II. The Third Paragraph of the Dispositif of the Judgment

10. The fact that the Court finds in the third paragraph of the dispositif of its Judgment that

"in the two channels around Kasikili/Sedudu Island, the nationals of, and vessels flying the flags of, the Republic of Botswana and the Republic of Namibia shall enjoy equal national treatment"

does not fully overcome the shortcomings of interpreting the term "main channel of that river,,l"Hauptlauf dieses Flusses" in favour of the northern channel. As far as the territorial status of the Island itself is [p1205] concerned, the third paragraph of the dispositif of the Judgment does not affect the finding in the second paragraph of the dispositif that the Island forms part of Botswana. As to the waters around the Island, conceding equal national treatment to the nationals of the other Party and to boats flying the flag of that Party, is not the same as the splitting of the "main channel"/"Hauptlauf of the Chobe around the Island, as originally envisaged by the Parties.

However, the fact that I do not regard the third finding in the dispositif of the Judgment as compensating for the erroneous decision in favour of the northern channel, has not prevented me from voting in favour of that finding. I agree with the reasons for the finding which are given in paragraphs 100 and 103 of the Judgment and the attribution, in the channels around Kasikili/Sedudu Island, of equal, national treatment to the nationals of both Parties and the boats flying their flags may be of some help to the Parties and contribute to avoiding or lessening tensions.

I have also come to the conclusion that the Court had jurisdiction to make the finding, as the Court is mandated by Article I of the Special Agreement by virtue of which it was seised with this dispute, "to determine . . . the legal status of the island"; that mandate comprises the determination of the legal status of the waters around Kasikili/Sedudu Island.
III. Final Remark: The Role of Prescription in This Case

11. As a final remark, I would like to add with regard to the role of prescription in this case, that I agree with the conclusion of the Judgment that acquisitive prescription does not play a role. I also agree with the reasons given for that conclusion. However, there is an additional and quite decisive reason why acquisitive prescription could not come into play in this case.

As the Court states, Botswana and Namibia

"agree between themselves that acquisitive prescription is recognized in international law and they further agree on the conditions under which title to territory may be acquired by prescription, but their views differ on whether those conditions are satisfied in this case" (Judgment, para. 96).

"For present purposes, the Court need not concern itself with the status of acquisitive prescription in international law or with the conditions for acquiring title to territory by prescription. It considers . .. that the conditions cited by Namibia itself are not satisfied in this case and that Namibia's argument on acquisitive prescription therefore cannot be accepted." (Judgment, para. 97.)[p1206]

These conclusions are not objectionable in themselves. The Court should however have gone into the conditions under which title to territory may be acquired by prescription, far enough to state that South Africa could not have acquired title to the Island by prescription. South Africa, whose presence in the Caprivi Strip including the Island lasted longer than the presence there of Germany or Britain, prior to the termination of the Mandate by the General Assembly in 1966 exercised authority there not a litre de souverain but a titre de mandataire. As mandatory, South Africa certainly was vested by virtue of the Mandate instrument of 17 December 1920 (League of Nations, Journal Officiel, 2nd Year, No. 1, p. 89) with the "full power of administration and legislation over the territory subject to the present Mandate as an integral portion of the Union of South Africa"; however, as the Court observes in its Advisory Opinion on the International Status of South West Africa (l.C.J. Reports 1950, p. 128, at p. 132):

"On the other hand, the Mandatory was to observe a number of obligations, and the Council of the League was to supervise the administration and see to it that these obligations were fulfilled."

And the Court added:

"The terms of this Mandate, as well as the provisions of Article 22 of the Covenant and the principles embodied therein, show that the creation of this new international institution did not involve any cession of territory or transfer of sovereignty to the Union of South Africa. The Union Government was to exercise an international function of administration on behalf of the League, with the object of promoting the well-being and development of the inhabitants." (Ibid.)

This perception of the nature of the Mandate is incompatible with acquisitive prescription working in favour of the Mandatory. After the termination of the Mandate, the continued presence of South Africa in South West Africa (Namibia) was no longer "peaceful", i.e., uncontested, as is confirmed by Security Council resolution 276 (1970) and by the Court's Advisory Opinion on the Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970) (I.C.J. Reports 1971, p. 16).

I agree that the present case is not a suitable occasion for the Court to concern itself with the status of acquisitive prescription in international law or with the general conditions under which title to territory may be acquired by prescription. Nevertheless, in order to further clarify the law [p1207] governing mandates or trusteeships, a statement of the Court that acquisitive prescription does not work in favour of a Mandatory would have been desirable.

(Signed) Carl-August Fleischhauer. [p1208]



DISSENTING OPINION OF JUDGE PARRA-ARANGUREN

The Anglo-German Agreement of 1890 — The Parties' differing interpretations of the 1890 Treaty — Subsequent practice as a rule of treaty interpretation — Subsequent practice of the Parties in the application of the 1890 Agreement — The Mandate for South West Africa (Namibia) — Relevant evidence submitted to the Court — Captain H. V. Eason's Report (1912) — Joint Report of 1948 (Trollope-Redman) and Exchange of Letters between 1948 and 1951 — Mr. R. R. Renew's Report (1965) — Witnesses called by Namibia — Evidence presented by Botswana — Maps — Aerial photographs and satellite images — Peaceful and public use of KasikililSedudu Island by Masubia Tribesmen from Eastern Caprivi — Conclusion.

I. The Anglo-German Agreement of 1890

1. In 1884 Germany proclaimed a Protectorate over the coast south of the Cape Colony's enclave at Walvis Bay and some years later, before 1890, expanded its territorial claims in South West Africa, without systematically establishing an effective administration on the ground. The United Kingdom decided to accept Germany's territorial claims in South West Africa, even though it regarded this territory as lying within Britain's natural sphere of influence.

2. The only area in dispute was Ngamiland, north of British Bechuana-land, a territory assigned to neither power and extending from the 20th to the 24th degree of longitude. Discussions began in 1886 but it was only in 1890 after the resignation of the German Chancellor Otto von Bis-marck that the new Chancellor, General Georg Leo Von Caprivi and his Foreign Minister, Baron Marschall, accelerated diplomatic discussions with Britain over Africa.

3. The Anglo-German Agreement relating to Africa and Heligoland was signed in Berlin, in English and in German, on 1 June 1890 by Sir Edward Baldwin Malet, Her Britannic Majesty's Ambassador Extraordinary and Plenipotentiary; Sir Henry Percy Anderson, Chief of the African Department of Her Majesty's Foreign Office; the Chancellor of the German Empire, General Leo Von Caprivi, and the Privy Councillor in the German Foreign Office, Dr. Friedrich Richard Krauel. The signature of the Treaty coincided with the declaration of British jurisdiction over Northern Botswana by Order-in-Council of 30 June 1890. [p1209]

4. Excluding the question of the Island of Heligoland, the British interest in this part of Africa was in controlling the area between Lake Ngami, some 350 kilometres to the south and west of Kasikili Island and the Victoria Falls, in order to protect the main trade routes from South Africa to the centre of the continent from encroachments by the Germans and Portuguese; while the Germans wanted to obtain the recognition of a German sphere of influence extending eastward, providing them access to the Zambezi. However, as Lord Salisbury informed Sir Edwin B. Malet, British Ambassador in Berlin, in his letter of 14 June 1890,

"The character of this country is very imperfectly known, and the very position of Lake Ngami has been the subject of considerable uncertainty." (Memorial of Botswana. Annexes, Vol. II, Ann. 7, p. 37.)
5. Lord Salisbury, in his speech to the House of Lords on 10 July 1890, referred to German aspirations in Africa, making clear that for Germany the conclusion of the agreement was subject to the condition that

"at the very north of this Damaraland territory they should have a strip of territory going along the Portuguese border, and giving them direct access to the River Zambesi... it is the last route in the world by which trade can pass. It is at the head of the waters of all the affluents of the Chobe and the Zambesi, over an impracticable country, and leading only into the Portuguese possessions."

6. On the same occasion Lord Salisbury also informed the House of Lords of the British interest in controlling Lake Ngami, even though he made the following comments:

"I think that the constant study of maps is apt to disturb men's reasoning powers . . . We have had a fierce conflict over the possession of a lake whose name I am afraid I cannot pronounce correctly — I think it is Lake Ngami — our only difficulty being that we do not know where it is. We cannot determine its position within 100 miles, certainly not within 60 miles, and there are great doubts whether it is a lake at all, or only a bed of rushes." (Memorial of Namibia, Annexes, Vol. IV, Ann. 31, p. 137.)

7. The above-mentioned aims pursued by Germany and Great Britain explain the terms in which Article III of the 1890 Anglo-German Agreement is drawn:

"In South-West Africa the sphere in which the exercise of influence is reserved to Germany is bounded:
………………………………………………………………………………………………
[p1210]
2. To the east by a line commencing at the above-named point [the point of intersection by the 20th degree of east longitude of a line commencing at the mouth of the Orange River, and ascending its north bank], and following the 20th degree of east longitude to the point of its intersection by the 22nd parallel of south latitude, it runs eastward along that parallel to the point of its intersection by the 21st degree of east longitude, thence it follows that degree northward to the point of its intersection by the 18th parallel of south latitude, it runs eastward along that parallel till it reaches the River Chobe; and descends the centre of the main channel of that river to its junction with the Zambesi, where it terminates.

It is understood that under this arrangement Germany shall have free access from her Protectorate to the Zambesi by a strip of territory which shall at no point be less than 20 English miles in width.

The sphere in which the exercise of influence is reserved to Great Britain is bounded to the west and north-west by the above-mentioned line. It includes Lake Ngami.

The course of the above boundary is traced in general accordance with a Map officially prepared for the British Government in 1889."
Furthermore, Article VI provides:

"All the lines of demarcation traced in Articles I to IV shall be subject to rectification by agreement between the two Powers, in accordance with local requirements."

Article VII adds:

"The two Powers engage that neither will interfere with any sphere of influence assigned to the other by Articles I to IV. One Power will not in the sphere of the other make acquisitions, conclude Treaties, accept sovereign rights or Protectorates, nor hinder the extension of influence of the other.

It is understood that no Companies nor individuals subject to one Power can exercise sovereign rights in a sphere assigned to the other, except with the assent of the latter." (Memorial of Botswana, Annexes, Vol. II, Ann. 12, pp. 206-207, 209-210.)

II. The Parties' Differing Interpretations of the 1890 Treaty

8. Namibia interprets the 1890 Anglo-German Agreement as follows:

"— The object and purpose of the Treaty was to divide the spheres of influence of Germany and Great Britain in Africa and to this [p1211] end to establish, where possible, firm, stable and visible boundaries between them. In the stretch of the Chobe River of concern in this case, the south bank of the River (including the right bank of the southern channel in the vicinity of Kasikili Island), is established by the Chobe Ridge, a stable and clearly visible escarpment some 50 metres high, so depicted on the map used by the negotiators, while the northern channel is in the midst of the floodplain of the Zambezi River and is inundated and invisible for nearly half of each year.

— The ordinary meaning of the 'channel' of a river is a conduit through which the water of the river flows, and the ordinary meaning of the 'main channel' is the channel that carries the major part of the flow of the river.

— The topographic, hydrological and geomorphologic characteristics of the Chobe River and the Zambezi floodplain establish that the southern channel carries not only the major portion, but substantially all of the flow of the River in the vicinity of Kasikili Island, while the northern channel has almost no longitudinal flow and is little more than a relict channel of the Zambezi floodplain".

Consequently, Namibia concludes:

"All the elements of interpretation converge on a single result: the southern channel is the main channel of the Chobe River around Kasikili Island. The Treaty therefore attributes the Island to Namibia." (Memorial of Namibia, Vol. I, p. 58, paras. 162-163.)

9. Botswana does not accept the conclusion of Namibia. In its opinion,
"the main channel of the Chobe in the vicinity of Kasikili/Sedudu Island is the northern and western channel, the principal criterion on which this assessment is based being that of navigability. In the absence of evidence to the contrary, the presumption must be that this was also the main channel at the time of the conclusion of the Anglo-German Agreement".

However, as alternative position Botswana accepts

"that, in accordance with the object and purpose of the Agreement, the main channel is constituted by the navigable channel at any given time, and that at present the northern and western channel is the main channel on this basis" (Memorial of Botswana, Vol. I, p. 52, paras. 116-117).

10. Therefore, Botswana and Namibia are not in agreement as to the meaning of Article III, paragraph 2, of the 1890 Anglo-German Treaty. The Treaty itself does not include a definition of the expression "the centre [p1212] of the main channel (der Thalweg des Hauptlaufes) of the Chobe River", nor do any other of its provisions provide by implication guidelines that might be useful for this purpose. Consequently, according to customary international law as expressed in Article 31 of the Vienna Convention on the Law of Treaties of 23 May 1969, the Court has to determine the meaning of such expression "in good faith", taking into account the rules of interpretation provided by the Convention (Oil Platforms (Islamic Republic of Iran v. United States of America), Preliminary Objection, Judgment, l.C.J. Reports 1966 (II), p. 812, para. 23.)

III. Subsequent Practice as a Rule of Treaty Interpretation

11. As a general rule of interpretation, Article 31, paragraph 3 (b), of the 1969 Vienna Convention on the Law of Treaties provides that account shall be taken, together with the context, of "any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation".

12. The International Law Commission has acknowledged that "[t]he probative value of subsequent practice is well recognized", because it shows how the intention of the parties has been put into effect. Moreover, the interpretation of treaties by reference to subsequent practice is well established in the jurisprudence of international tribunals and, more especially, of the World Court (Yearbook of the International Law Commission, 1964, Vol. II, p. 59).

13. Thus the Permanent Court of International Justice, in its Opinion on the Competence of the ILO in Regard to International Regulation of the Conditions of Labour of Persons Employed in Agriculture, stated:

"If there were any ambiguity, the Court might, for the purpose of arriving at the true meaning, consider the action which has been taken under the Treaty." (1922, P.C.I.J., Series B, No. 2, p. 39.)

14. Similarly, this Court, in the Corfu Channel case found that:
"The subsequent attitude of the Parties shows that it was not their intention, by entering into the Special Agreement, to preclude the Court from fixing the amount of the compensation." (/. C.J. Reports 1949, p. 25.)

15. Later pronouncements of this Court have confirmed the importance of subsequent practice for the interpretation of a Treaty, as is indicated in paragraph 50 of the Judgment.

16. Subsequent practice can be relevant either as a means of establishing the parties' agreement to the Treaty's interpretation or in order to shed light on their original intentions. It is possible that the conduct of [p1213] the parties may have been at variance with the provisions of the Treaty, showing disregard for the natural and ordinary meaning of its terms. In such cases, "there may be a blurring of the line between the interpretation and the amendment of a treaty by subsequent practice", even though these two processes are legally quite distinct. In the opinion of the Inter-national Law Commission this was exactly what happened in the Temple of Preah Vihear case, where the line of action taken by the parties was not reconcilable with the natural and ordinary meaning of the terms of the Treaty. The Commission therefore concluded that the effect of sub-sequent practice on that occasion was to amend the Treaty (Yearbook of the International Law Commission, 1964, Vol. II, p. 60).

17. The practice of an individual State may have special cogency when it relates to the performance of an obligation which particularly concerns that State, as was stated by the Court in its Opinion on the International Status of South West Africa (I.C.J. Reports 1950, pp. 135-136). However, subsequent practice as a means of interpretation of bilateral treaties requires the agreement of both parties. Such agreement may be expressed through their joint or parallel positive activity, but it may also be ascertained from the activity of only one of the parties, where there is assent or lack of objection by the other party. As is remarked by the International Law Commission, it is sufficient that the other party accepts that practice (United Nations Conference on the Law of Treaties - First and Second Sessions: Documents of the Conference (1968-1969), p. 42, para. 15).

18. The importance of the silence of one party in determining the subsequent practice of the parties to a bilateral treaty was admitted very recently in the Beagle Channel arbitration case, where it was stated:

"the Court cannot accept the contention that no subsequent conduct, including acts of jurisdiction, can have probative value as a subsidiary method of interpretation unless representing a formally stated or acknowledged 'agreement' between the Parties. The terms of the Vienna Convention do not specify the ways in which 'agreement' may be manifested. In the context of the present case the acts of jurisdiction were not intended to establish a source of title independent to the terms of the Treaty; nor could they be considered as being in contradiction of those terms as understood by Chile. The evidence supports the view that they were public and well-known to Argentina, and that they could only derive from the Treaty. Under these circumstances the silence of Argentina permits the inference that the acts tended to confirm an interpretation of the meaning of the Treaty independent of the acts of jurisdiction themselves." (International Law Reports, Vol. 52, p. 224, para. 169.) [p1214]
IV. Subsequent Practice of the Parties in the Application of the 1890 Anglo-German Agreement

19. Namibia maintains that the subsequent conduct of the parties to the 1890 Anglo-German Agreement demonstrates that Kasikili Island is part of Namibia. It bases its contention upon

"The control and use of Kasikili Island by the Masubia of Caprivi, the exercise of jurisdiction over the Island by the Namibian governing authorities, and the silence by Botswana and its predecessors persisting for almost a century with full knowledge of the facts." (Memorial of Namibia, Vol. I. p. 60, para. 166.)

20. During the oral pleadings Namibia insisted on "continued presence of the Masubia on the ground under colonial rule plus the acceptance of the situation by Botswana's predecessors" (CR99/10, p. 27, para. 21 (Chayes)). In its opinion, the Masubia people of the Eastern Caprivi occupied the Island from 1890 to at least until the mid-1960s. Then, from the time the German officials first arrived in 1909, they and their successors incorporated the local institutions of the Masubia into the structure of colonial governance, using them as instruments for implementing their suzerainty; and the activities carried on by them were under the rule of the indigenous Masubia authorities — the chief, his kuta and the indunas, or local representatives. All these facts were well known to the Bechuanaland authorities just across the river in Kasane, but they made no objection or protest, at least until 1948. From this interactive pattern, Namibia concludes, it can be seen that the parties were in agreement that the Treaty, properly interpreted, attributed Kasikili Island to Namibia (CR 99/11, p. 41, para. 6 (Chayes)).

21. In this respect Botswana observes that

"The Namibian argument based upon subsequent conduct of the parties rests upon extraordinarily weak foundations, both in conceptual and in factual terms. The conceptual foundations are weak because in truth, the 'subsequent conduct' argument of Namibia is an argument grounded in acquisitive prescription. Thus, subsequent conduct, which relates to an existing legal instrument, is opposed to prescription, the purpose of which is to destroy and to supplant a pre-existing title." (Reply of Botswana, Vol. I, p. 55, para. 157.)

22. However, Namibia states very clearly in its Memorial that the subsequent conduct of the parties to the 1890 Anglo-German Agreement

"is relevant to the present controversy in three distinct ways. In the first place, it corroborates the interpretation of the Treaty . . . Second, it gives rise to a second and entirely independent basis for Namibia's claim under the doctrines concerning acquisition of terri-[p1215]tory by prescription, acquiescence and recognition. Finally, the conduct of the parties shows that Namibia was in possession of the Island at the time of termination of colonial rule, a fact that is pertinent to the application of the principle of uti possidetis." (Memorial of Namibia, Vol. I, p. 60, para. 165.)

23. Furthermore, in its oral pleadings Namibia stressed that "its primary claim is that its title is treaty based"; that its claim "of prescription is asserted in the alternative"; and that
"the very meaning of the ability to plead in the alternative is that each claim is to be considered in its own right, and no inference is to be taken against one claim because an inconsistent claim has been pleaded" (CR 99/10, p. 24, para. 10 (Chayes)).

24. Consequently, the Court has to examine in the first place the primary claim presented by Namibia, i.e., subsequent practice as a means of interpretation of the 1890 Anglo-German Agreement; and only if Namibia's primary claim fails will the Court have to examine the alter-native claims, based upon prescription, acquiescence and recognition, presented by Namibia to demonstrate its ownership of Kasikili Island.

V. The Mandate for South West Africa (Namibia)

25. Following the outbreak of the First World War, the Eastern Caprivi was occupied in September 1914 without resistance by paramilitary police from Southern Rhodesia. Captain Eason was appointed Special Commissioner for the Caprivi Zipfel on 6 November 1914 and took up his duties at Schuckmannsburg on 20 November. As stated in the Resident Commissioner's Report on the Administration of the Caprivi Zipfel during the period 1914 to 31 March 1922, "It was not desired that authority should be asserted to a greater extent or over a wider area than was absolutely essential." (Memorial of Namibia, Ann. 52, p. 203.)

26. By Article 119 of the Treaty of Peace signed at Versailles on 28 June 1919, Germany renounced in favour of the Principal Allied and Associated Powers all her rights over her overseas possessions, including therein German South West Africa.

27. Article 22, paragraph 1, of the League of Nations Covenant provided that:

"To those colonies and territories which as a consequence of the late war have ceased to be under the sovereignty of the States which formerly governed them and which are inhabited by peoples not yet able to stand by themselves under the strenuous conditions of the [p1216] modern world, there should be applied the principle that the well-being and development of such peoples form a sacred trust of civilisation and that securities for the performance of this trust should be embodied in this Covenant."

28. Paragraph 2 of the same Article 22 added that:

"The best method of giving practical effect to this principle is that the tutelage of such peoples should be entrusted to advanced nations who by reason of their resources, their experience or their geographical position can best undertake this responsibility, and who are willing to accept it, and that this tutelage should be exercised by them as Mandatories on behalf of the League."

29. Article 22, paragraph 6, of the League of Nations Covenant supplemented the mandate's system by providing that

"territories, such as South-West Africa and certain of the South Pacific Islands, which, owing to the sparseness of their population, or their small size, or their remoteness from the centres of civilisation, or their geographical contiguity to the territory of the Manda-tory, and other circumstances, can be best administered under the laws of the Mandatory as integral portions of its territory, subject to the safeguards above mentioned in the interests of the indigenous population".

30. Furthermore, Article 22 provided that the Mandatory shall render to the Council of the League of Nations an annual report in reference to the territory committed to its charge (para. 7); that a permanent Commission shall be constituted to receive and examine the annual reports of the Mandatories and to advise the Council on all matters relating to the observance of the mandates (para. 9); and that

"The degree of authority, control, or administration to be exercised by the Mandatory shall, if not previously agreed upon by the Members of the League, be explicitly defined in each case by the Council." (Para. 8.)

31. The Principal Allied and Associated Powers agreed that a Mandate over the territory which formerly constituted the German Protectorate of South West Africa should be conferred upon His Britannic Majesty, to be exercised on his behalf by the Government of the Union of South Africa. His Britannic Majesty, for and on behalf of the Government of the Union of South Africa, agreed to accept the Mandate and undertook to exercise it on behalf of the League of Nations in accordance with the terms defined by its Council on 17 December 1920, which con-firmed a prior decision taken on 7 May 1919.

32. According to the terms of South West Africa's mandate, the consent of the League of Nations was required for the modification of its provisions (Art. 7, para. 1); and the authority of the Union of South Africa was defined by Article 2 as follows: [p1217]

"The Mandatory shall have full power of administration and legislation over the territory subject to the present Mandate as an integral portion of the Union of South Africa, and may apply the laws of the Union of South Africa to the territory, subject to such local modifications as circumstances may require.

The Mandatory shall promote to the utmost the material and moral well-being and the social progress of the inhabitants of the territory subject to the present Mandate." (League of Nations, Official Journal, January-February 1921, p. 89.)

33. Until 31 December 1920 the Strip was ruled as a de facto part of the Bechuanaland Protectorate under martial law. Martial law in the Eastern Caprivi was ended by the Governor General's Proclamation No. 12 of 1922 and High Commissioner's Proclamation No. 23 of 1922, which placed the Strip under civilian Protectorate authority retroactively from 1 January 1922 (Memorial of Botswana, Annexes, Vol. Ill, Ann. 19, p. 257.)

34. The Mandate of the Union of South Africa over South West Africa continued after the dissolution of the League of Nations, even though it was expected that the mandated territories, which had not become independent, should be placed under the trusteeship system of the United Nations. Notwithstanding, among the mandatory powers, only the Union of South Africa refused to do this in respect to the territory of South West Africa, because in its opinion the mandate had lapsed. As a result, the Union of South Africa not only refused to comply with its obligations under the Covenant and the Mandate but also invoked the special position of the mandated territory as a reason for making it a part of its territory. For this reason the General Assembly of the United Nations decided to request an Advisory Opinion from the Court on the matter.

35. The Court stated in its Advisory Opinion of 11 June 1950 that the creation of the Mandate:

"did not involve any cession of territory or transfer of sovereignty to the Union of South Africa. The Union Government was to exercise an international function of administration on behalf of the League, with the object of promoting the well-being and development of the inhabitants." (I.C.J. Reports 1950, p. 132.)

36. Furthermore, the Court added that

(a) "the Union of South Africa continues to have the international obligations stated in Article 22 of the Covenant of the League of Nations and in the Mandate for South-West Africa" (ibid., p. 143);
(b) "the General Assembly of the United Nations is legally qualified to exercise the supervisory functions previously exercised by the League [p1218]of Nations with regard to the administration of the Territory, and that the Union of South Africa is under an obligation to submit to supervision and control of the General Assembly and to render annual reports to it" {I.C.J. Reports 1950, p. 137);
(c) "It is clear that the Union has no competence to modify unilaterally the international status of the Territory or any of these international rules", as "is shown by Article 7 of the Mandate, which expressly provides that the consent of the Council of the League of Nations is required for any modification of the terms of the Mandate" {ibid., p. 141);
and
(d) "that the Union of South Africa acting alone has not the competence to modify the international status of the Territory of SouthWest Africa, and that the competence to determine and modify the international status of the Territory rests with the Union of South Africa acting with the consent of the United Nations" {ibid., p. 144).

37. The Union of South Africa's mandate over South West Africa was terminated by United Nations General Assembly resolution 2145 (XXI) of 1966; and its resolution 2248 (S-V) of 1967 entrusted the administration of South West Africa, with the new name of Namibia, to the Secu-rity Council. Furthermore, due to its refusal to withdraw from the territory, Security Council resolution 176 of 1970 declared South Africa's presence in Namibia (South West Africa) illegal; that illegality was confirmed by the Court in its Advisory Opinion of 26 January 1971 on the Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council resolution 276 (1970) {I.C.J. Reports 1971, p. 58, para. 113) (see para. 69 of the Judgment).

38. The legal position of the Union of South Africa did not change during the existence of its mandate over South West Africa. The powers of the Union of South Africa over the territory of South West Africa were only administrative and legislative; they had to be exercised to "promote to the utmost the material and moral well-being and the social progress of the inhabitants". Acts of disposition of the territory of the mandate were outside the powers conferred on the Mandatory. Therefore, the Union of South Africa could not undertake such acts.

39. The British authorities acknowledged this legal situation in 1949, when examining the possibility of entering into an agreement with the Union of South Africa, as Mandatory Power for South West Africa, regarding Kasikili Island. Mr. G. H. Baxter, Commonwealth Relations Office, examined the proposal made by the Union of South West Africa to set the boundary in the southern channel of the Chobe River, guaranteeing the use of the northern channel for navigation by the inhabitants [p1219] and authorities of the Bechuanaland Protectorate (Letter of 14 October 1948 to the High Commissioner's Office in Pretoria, Memorial of Namibia, Vol. IV, Ann. 63, p. 280; Memorial of Botswana, Annexes, Vol. Ill, Ann. 23).

40. Mr. Baxter's Report of 20 October 1949 to Sir Evelyn Baring, High Commissioner for Basutoland, the Bechuanaland Protectorate and Swaziland, commented on the international aspect of the matter in the following terms:

"This is governed largely by the question whether the mandate is still regarded as effective. It is understood that the view of the Union Government is that the mandate has expired. [Mr. Baxter's Report was prepared in 1950 before the Court gave its Advisory Opinion on the matter.] This view, however, is not universally shared by other Governments and the position under International Law seems to be obscure. The mandate is limited, by the preamble and Article 1, to the territory which formerly constituted the German Protectorate of South West Africa. By Article III of an Agreement made in 1900 with Germany, the boundary at this point was fixed at the centre of the main channel of the river and if, as now appears to be the case, the main channel was at all material times on the north side of the island in question, the mandated territory did not include the island. Under Article 7 of the Mandate no modification could be made without the consent of the Council of the League of Nations. In so far as the mandate is still operative, this might be interpreted as referring to some organ of the United Nations or as making any adjustment impossible. No doubt it is unlikely that anyone would raise any objection in the United Nations, especially as the proposal is to add to the territory and not in any way to reduce its area, but the possibility cannot be entirely ignored." (Memorial of Botswana, Vol. Ill, Annexes, Ann. 28, p. 288.)

Furthermore Mr. G. H. Baxter added the following observations:

"Article VI of the Agreement of 1900 provides that 'the lines of demarcation traced in Articles I to IV shall be subject to rectification by agreement between the two Powers, in accordance with local requirements'. It might be argued that this now operates to permit the boundary to be varied, for the purposes of both international and municipal law, by agreement between the United Kingdom Government and the Government of the Union as successor of the German Government. It is, however, doubtful whether the argument would be sound, since rectification would alter what is in fact, the boundary of the former German Protectorate. As between these two Governments, Article VI is probably still effective, but we are [p1220]here concerned with a document (the Mandate) in which others are interested." (Memorial of Botswana, Vol. Ill, Annexes, Ann. 28, pp. 290-291.)

41. Taking into account these considerations, the High Commissioner's Office, Pretoria, concluded that "it would seem desirable to let sleeping dogs lie" (19 November 1949 Letter of High Commissioner, Pretoria, to V. F. Ellenberger, Memorial of Botswana, Annexes, Vol. Ill, Ann. 29, p. 296). Therefore, the High Commissioner, Sir Evelyn Baring, took the decision not to enter into a formal agreement, and his letter of 10 May 1951 explained to Mr. Forsyth of the South African Department of External Affairs, that the matter was "beset by legal complications of an international nature, the solution of which would entail difficulties disproportionate to the importance of the matter at issue" (Memorial of Namibia, Vol. IV, Ann. 69, p. 294; Memorial of Botswana, Annexes, Vol. Ill, Ann. 30, p. 298; CR99/7, p. 12 (Brownlie)).

42. Consequently, after the confirmation of the creation of the mandate by the Council of the League of Nations in 1920, the Union of South Africa could not dispose by its own actions of the territory of South West Africa, as it had been determined by the subsequent practice of the parties to the 1890 Anglo-German Agreement.

43. For this reason, 1914 is the latest date to be taken into account for the determination of the subsequent practice of the parties, Germany and Great Britain, in regard to the interpretation of Article III of the 1890 Anglo-German Agreement. In fact, no subsequent practice could exist on the part of Germany after September 1914 when the Eastern Caprivi was occupied by Southern Rhodesia. During the existence of the mandate the Union of South Africa had no competence either to enter into any express agreement to delimit the international boundary of South West Africa or to modify the prevailing subsequent practice with regard to the interpretation of Article III of the 1890 Anglo-German Agreement. Consequently, in my opinion, the subsequent practice of the parties for the purpose of interpreting the Anglo-German Agreement should be determined on the basis of the situation existing up to September 1914.

VI. Relevant Evidence Submitted to the Court

44. The Court stated in its Judgment of 26 November 1984 that "it is the litigant seeking to establish a fact who bears the burden of proving it" {Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Jurisdiction and Admissibility, Judg-ment, I.C.J. Reports 1984, p. 437, para. 101; cf. also Frontier Dispute (Burkina Faso/Republic of Mali), I.C.J. Reports 1986, p. 587, para. 65).

45. For this reason the Court has to examine in the present case the evidence presented by Namibia to support its contention that the subse-[p1221]quent practice of the parties to the 1890 Anglo-German Agreement demonstrates that they considered the southern channel of the Chobe River as the "main channel" referred to in Article III of that Agreement; and that, therefore Kasikili Island was part of Namibia. Thus the facts indicative of the subsequent practice of the parties alleged by Namibia are:

"(1) continuous, open and notorious occupation and use of the territory in question over a long period of time; (2) exercise of sovereignty in the territory; and (3) failure of the other party, having knowledge of these facts, to object, protest or assert its rights" (Memorial of Namibia, Vol. I, p. 66, para. 180).

46. The evidence to be examined is the following:

A. Captain H. V. Eason's Report (1912)

47. An exchange of communications took place between Great Britain and Germany at the beginning of the century, dealing with the western half of the southern boundary line established by the 1890 Anglo-German Treaty. On 14 January 1911 Lord Harcourt, the Secretary of State of the Colonial Office, instructed the High Commissioner of the Bechuanaland Protectorate to gather "all available information from local sources in support of the view that the north channel is the main channel" of the Chobe river around Kasikili Island (Memorial of Namibia, Vol. IV, Ann. 44, p. 170).

48. This despatch led to Captain H. V. Eason's Report, dated 5 August 1912, where he states:

"Two miles above the rapids lies Kissikiri Island. Here I consider that undoubtedly the North should be claimed as the main channel. At the Western end of the island the North Channel at this period of the year is over one hundred feet wide and eight feet deep, the South Channel about forty feet wide and four feet deep. The South Channel is merely a back water, what current there is goes round the North. The natives living at Kasika in German territory are at present growing crops on it." (Memorial of Namibia, Vol. IV, Ann. 47, p. 177.)

49. Even though Captain Eason stated that the northern channel "should be claimed as the main channel", he acknowledged that "the natives living at Kasika in German territory are at present growing crops on it", meaning Kasikili Island. [p1222]

B. Joint Report of 1948 (Trollope-Redman) and Exchange of Letters between 1948 and 1951

50. The 1948 Joint Report prepared by L. F. W. Trollope and Noel W. Redman, as well as its antecedents and the correspondence that followed between 1948 and 1951, are comprehensively reviewed in paragraphs 56 to 61 of the Judgment. The relevant extracts need not therefore be reproduced here. In my opinion those documents demonstrate:

(a) that the Masubia of the Eastern Caprivi were the only tribesmen who used the Island for cultivation not only until 1914, i.e., the critical date for the purpose of interpreting the 1890 Anglo-German Agreement, but also until 1947 when the border dispute arose between the Parties;

(b) that during the same period neither the Bechuanaland tribesmen nor the Bechuanaland Protectorate authorities ever complained about that use;

(c) that the Bechuanaland Protectorate tribesmen had never used the Island either for cultivation or for other purposes; and
(d) that the Bechuanaland tribesmen and Bechuanaland Protectorate authorities enjoyed undisputed use of the northern channel of the Chobe River around Kasikili Island.

These conclusions are accepted in the Judgment, where it is stated:

"From the various administrative and diplomatic documents referred to above, the Court, for its part, observes the following: (1) prior to 1947 no differences had arisen between Bechuanaland and the power administering the Caprivi Strip with regard to the boundary in the area of Kasikili/Sedudu Island; (2) it appears that, on the basis of the maps available at the time, the boundary had until then been supposed to be located in the southern channel of the Chobe . . ." (Para. 62.)

C. Mr. R. R. Renew's Report (1965)

51. In response to a request for information about Kasikili Island from the Department of Public Works, Mr. R. R. Renew, Surveyor-General of the Bechuanaland Protectorate, prepared his report of 10 October 1965. In the first place Mr. Renew recalled:

"Kasikili island became the subject of a dispute in 1947 when the Native Commissioner of the eastern Caprivi Strip was alleged to have challenged Bechuanaland's right to the use of the main channel of the Chobe River along the north side of the island, as a water-way." (Memorial of Botswana, Annexes, Vol. Ill, Ann. 36, p. 321.) [p1223]

Then, after reviewing the Trollope-Dickinson exchange of letters (19481951), Mr. Renew concluded that "It appears, therefore, that if we now wish to use the island we have no alternative but to re-open the matter". Furthermore he added:

"I think that the South African case for possession of this island is very weak. The fact that we did not use it, and allowed the Caprivi tribesmen to use it, does not amount to prescription so much as tolerating its use by the Caprivi people while it was inconvenient for us to use it." (Memorial of Botswana, Annexes, Vol. Ill, Ann. 36, p. 325.)

52. Thus, the facts stated by Mr. R. R. Renew in his Report coincide with the conclusions already reached in this opinion (see para. 50 above).

D. Witnesses called by Namibia

53. The statements in May and June 1994 by Namibia's witnesses before the Joint Technical Team of Experts confirm that only the Masubia of the Eastern Caprivi used Kasikili Island for ploughing; that no one from the Bechuanaland Protectorate had ever used the Island; that permission to use the Island was only ever sought or obtained from the Masubia authorities; and that these activities were known at the time to the British authorities.

54. Botswana maintains that those statements cannot be accepted because of the contradictions that emerged when the witnesses were cross-examined. In particular it stresses that Chief Moraliswani, when asked about the date people stopped ploughing on Kasikili Island, answered:
"That was in 1937 when now a lot of elephants were now entering Caprivi and then when people were ploughing it was found that those elephants were destroying their fields, it's when they decided to move and come to the other side here in Caprivi." (Memorial of Namibia, Annexes, Vol. Ill, Ann. 2, p. 209.)

Therefore Botswana concludes that the cultivation of the Island ceased in 1937 (Counter-Memorial of Botswana, Vol. I. p. 205, para. 468).

55. However, as stated before, the subsequent practice of the parties for purposes of interpreting the 1890 Anglo-German Agreement has to be examined only until 1914 (see Section V of this opinion). Therefore, Botswana's contention that cultivation of Kasikili Island took place only until 1937 is irrelevant. Besides, even though Namibia's witnesses sometimes contradict themselves in details, the bulk of their statements is consistent and for this reason, in my opinion, the statements should be [p1224] accepted as valid evidence. Consequently, this objection by Botswana cannot be upheld.

56. Additionally, Botswana contends that extraneous oral evidence would only be relevant if it were intended to shed some light on either the actual intentions of the parties to the 1890 Anglo-German Agreement or on the ordinary meaning at the material time (1890) of the phrase "the centre of the main channel of [the] river" included in its Article III. Consequently, in Botswana's view extraneous oral evidence of alleged activities on the Island as evidence of subsequent practice is of no legal relevance for purposes of determining the boundary between Namibia and Botswana on the basis of the Anglo-German Agreement of 1890 (Counter-Memorial of Botswana, p. 203, para. 461; CR 99/12, pp. 10-11 (Tafa)).

57. The Joint Team of Technical Experts was created as a consequence of the Communiquι issued on 24 May 1992 by the President of Botswana, the President of Namibia and the President of Zimbabwe (Memorial of Botswana, Vol. Ill, Annexes, Ann. 55, pp. 413-415); and the Memorandum of Understanding regarding its terms of reference, signed by Namibia and Botswana on 23 December 1992, expressly permits the taking of oral evidence. Thus, Article 7, paragraph 1, of the Memorandum of Understanding provides that

"In the execution of its functions, the Team shall have authority to:
………………………………………………………………………………………………
(f) hear, without prejudice to the 1890 and 1892 Treaties, any oral evidence from any competent person in Botswana and Namibia or from any other country which the Team may consider necessary to enable it to arrive at a decision on the Kasikili/Sedudu Island dispute." (Memorial of Botswana, Annexes, Vol. Ill, Ann. 57, pp. 433-434.)

58. Consequently the 1992 terms of reference did not restrict witness testimony to the demonstration of the actual intentions of parties to the 1890 Anglo-German Agreement, or of the ordinary meaning of the words "the centre of the main channel of the river" at the material time (1890), as Botswana claims. Witness evidence was declared admissible in general terms, whenever appropriate, to demonstrate facts relevant to the boundary dispute over Kasikili/Sedudu Island. Therefore Namibia called witnesses to demonstrate the subsequent conduct of the parties as a means of interpretation of the 1890 Anglo-German Agreement. For the same reason Botswana presented and relied upon the statements of its witnesses as good evidence to contradict the subsequent practice asserted by Namibia and to prove that the Masubia from the Eastern Caprivi Zipfel were not the only persons who used Kasikili Island. Consequently, in my opinion, this objection of Botswana cannot be upheld. [p1225]

E. Evidence presented by Botswana

59. (1) Botswana presented affidavits by the following persons: (a) Dominic Diau (dated 6 October 1997); Brian Egner (dated 19 September 1997); Peter Gordon Hepburn (dated 6 August 1997); Timothy Neville Liversedge (dated 30 October 1997); and Michael Slogrove (dated 8 July 1997) (Counter-Memorial of Botswana, Anns. 47-51); and (b) Botsweletse Kingsley Sebele (dated 14 August 1998); Michael Slogrove (dated 24 August 1998); and Simon Adolph Hirschfield (dated 25 August 1998) (Reply of Botswana, Vol. I, Anns. 20-22).


60. The statements embodied in the above-mentioned affidavits limit themselves to facts that took place between 1977 and 1979; 1959 and 1962; 1962 and 1970; 1969 and 1970 and 1972 and 1978, respectively (Counter-Memorial of Botswana, Anns. 47-51); and between October 1971 and April 1975; 1972 and 1978 and 1971 and 1995 (Reply of Botswana, Anns. 20-22). Therefore, in my opinion, they are not relevant to the subsequent practice of the parties to the 1890 Anglo-German Agreement in 1914, which is the critical date; nor even in 1947 when the dispute arose for the first time between the Parties (see Section V of this opinion).

61. (2) Mr. Noel Redman, the District Commissioner at Kasane, in the cover letter of 26 January 1948 (para. 5), attaching his and Mr. Trol-lope's Joint Report, reported to the Government Secretary (Maefeking) the following:

"Since the attached report was prepared I have received further information from an inhabitant of the Island that in 1924 a Caprivi Chief named Liswaninyana applied to Captain Neale (sic Nellie), the Resident Magistrate at Kasane, for permission for his people to plough on the Island and graze cattle there. This was evidently granted verbally and no written agreement is known. At this time Government Oxen were grazing on the Island but they were removed in 1925. Before 1924 the same informant told me that there was one Caprivi family ploughing there but they had no authority to do so." (Memorial of Botswana, Annexes, Vol. Ill, Ann. 22, p. 265; CR99/7, pp. 23-24 (Brownlie).)

62. However, the additional information reported by Mr. Redman refers to acts which occurred after 1914, the critical date for determining the subsequent practice of the parties in order to interpret the 1890 Anglo-German Agreement. Moreover, the witness testimony reported by Mr. Redman was merely hearsay. Furthermore, as Namibia observes,

"in 1924 Captain Neale had a dual role. He was both District Commissioner for Kasane in the Bechuanaland Protectorate and admin-[p1226] istrator of the Eastern Caprivi under the League of Nations Mandate for South-West Africa. Thus, even if he had authorized Liswanin-yana to cultivate on the Island, this action would not necessarily prove that the Protectorate exercised control over the Island. Given Captain's Neale's dual functions, his alleged authorization to use Kasikili Island cannot be properly assessed without first determining whether he was acting as administrator of the Eastern Caprivi or as administrator of the Bechuanaland Protectorate's District of Kasane." (Reply of Namibia, p. 108, para. 244.)

63. (3) Botswana relies on the fact that it was not until 6 March 1992 that Namibia made any representation complaining about its people being unable to use Kasikili Island, notwithstanding that they ceased to do so in 1937, according to the statements made by Chief Moraliswani, or in 1958 as some of Namibia's witnesses testified (CR99/7, p. 25 (Brownlie)). However, 1914 is the critical date for determining the subsequent practice of the Parties. Therefore these facts, which took place afterwards are irrelevant because of the existence of the mandate over South West Africa.

64. (4) According to Botswana, no group had exclusive use of the Island for farming purposes because in the 1940s seven families of Barotse migrants lived in the Sedudu area, the term Batoka being the local Chobe name for people coming from what is now part of Zambia, and worked fields on the Island. Botswana maintains that this fact is evidenced by the Chobe annual reports attached to Botswana's Reply (Anns. 7 and 8). (Reply of Botswana, p. 45, para. 125; Annexes, Anns. 7 and 8, pp. 14-20, 21-22; CR99/7, p. 25 ( Brownlie)). Furthermore, Botswana stresses that one of the witnesses, Keorapetse Mokhiwa, a 70 year-old peasant, said "fields were very small because people used to plough with hand, these hand ploughs" (CR99/8, p. 13, para. 4.5 (Fox)).

65. However, this contention is not relevant per se, because it refers to facts which occurred after 1914, the critical date for the determination of the subsequent practice of the Parties for the purpose of interpreting Article III of the 1890 Anglo-German Agreement. Furthermore, Sedudu is a name identifying not only Kasikili Island but also Sedudu Valley on the Botswana side of the River Chobe. Therefore, even admitting that those families were living and working in "Sedudu", it has not been demonstrated that "Sedudu" in this specific case meant Kasikili Island.

66. (5) In its oral pleadings Botswana stressed that the exchange of letters between Messrs. Trollope and Dickinson (1948-1951) maintained the status quo ante. However, in my opinion, the status quo ante favours Namibia's position as to the subsequent practice of the Parties (see para. 50 above). [p1227]

67. (6) Botswana recalls the establishment by the British authorities of the Chobe Game Reserve in 1960, its northern delimitation corresponding with the international boundary between the Bechuanaland Protectorate and South West Africa. For this reason, in the opinion of Botswana, no cultivation has taken place on the Island since 1960 and, of course, in fact it had almost certainly ceased many years before (CR99/7, p. 27 (Brownlie)). However, this argument is not relevant because 1914 is the critical date for determining the subsequent practice of the parties to the 1890 Anglo-German Agreement. Besides, as pointed out by Namibia, the Act creating the Chobe Game Reserve in 1960 refers to the 1933 British War Office GSGS 3915 Map, which indicates the southern channel as the international boundary (CR99/1, p. 40, para. 64 (Chayes)).

68. (7) Botswana points out that, on the occasion of the planned visit of the President of Botswana to the vicinity of the Island in 1972, Mr. Slogrove stated:
"The landing on this Island of a fully armed squad of the Botswana P.M.U. in August, 1972, during the Presidents visit for the purpose of searching it as a security measure strengthened my conviction that this Island was regarded as Botswana Territory." (Reply of Botswana, Annexes, Ann. 10, p. 25; CR99/7, p. 28 (Brownlie)).

The two affidavits by Mr. Slogrove have already been examined and considered irrelevant because they refer to facts posterior to 1914, which is the critical date for determining the subsequent practice of the parties as a means of interpretation of the 1890 Anglo-German Agreement.

69. (8) For the same reason, the meeting of delegations of the Parties at Katima Mulilo in 1981, the eventual Pretoria Agreement of 1984 and the Botswana Note to South Africa dated 22 October 1986, referred to by Botswana (CR 99/7, p. 28 (Brownlie)), are irrelevant for the purpose of demonstrating the subsequent practice of the parties to the 1890 Anglo-German Agreement.

70. (9) Botswana also recalls that some ten of its witnesses gave evidence that they had been engaged in trekking cattle from Maun to the ferry at Kazungula in the 1930s and 1940s; and that they grazed cattle on Kasikili Island (CR99/8, p. 26 (Fox)). However, those activities are also irrelevant to a determination of the subsequent practice of the Parties in 1914, which is the critical date for that purpose.

F. Maps

71. Since the critical date is 1914, all maps prepared afterwards are irrelevant to an interpretation of the 1890 Anglo-German Agreement by [p1228] reference to the subsequent practice of the parties. Therefore the only maps that need to be examined are the following.

72. (1) The ID 776 Map (1889) made by the British War Office, referred to in the 1890 Anglo-German Agreement, and the Map of Southern Zambezia (1891). However, neither is of any use because no boundary symbol appears along the Chobe River.

73. (2) The Kriegskarte 1:800,000 (1904) has a label indicating "Sulumbu's Island". However, as Namibia remarks, "the reproductions of this map in the Botswana Atlas (maps 4 and 5), on which Botswana seems to rely for analysis, are extremely poor and are not two maps but two copies of one map" (CR 99/4, p. 56 (Rushworth)). Botswana accepted those criticisms and acknowledged that "[t]he map depicts some features which are now not in conformity with the known geographical features" (Reply of Botswana, p. 71, para. 206). The map was not even mentioned by Botswana in its oral pleadings (CR 99/14, p. 27 (Fox)). Therefore, in my opinion, it is irrelevant.

74. Seiner's Map 1:500,000 (1909) shows Kasikili Island, even though labelled "Sulumbu's Island". However, as Namibia acknowledges, the key to the map "does not say how international boundaries are portrayed" (CR99/4, p. 43 (Rushworth)). Therefore it is irrelevant for the purpose of determining the boundary line at Kasikili Island.
75. Streitwolfs Map 1:200,000 (1910) depicts Kasikili Island under the name "Kassikiri". However, it is irrelevant since no boundaries are shown, as Namibia points out (CR 99/4, p. 44 (Rushworth)).

76. Von Frankenberg's Map 1:100,000 (1912) shows Kasikili Island, again under the name "Kassikiri". The German word "Flussarm" appears above the southern channel and because of that Botswana concludes that the southern channel is not the "main channel" but a "side branch" of the Chobe River. Notwithstanding, Botswana has maintained that its case "is not based on maps, by reason of their lack of accurate information and their inconsistency" (Reply of Botswana, p. 99, para. 258). Moreover, the map does not show the international boundaries between the two countries. For this reason, in my opinion, it is irrelevant.

77. Hence none of the relevant maps which were submitted to the Court can serve to demonstrate the subsequent practice of the Parties for the purpose of interpreting the 1890 Anglo-German Agreement, bearing in mind that 1914 is the critical date for such demonstration. Consequently, in my opinion, it is not necessary to consider any questions relating to the cartographic principles governing the preparation of maps or the conditions which maps must satisfy in order to produce legal consequences, or their importance in the resolution of legal disputes. [p1229]

G. Aerial Photographs and Satellite Images

78. The aerial photographs and satellite images submitted to the Court do not contain any indication which would enable it to determine the boundary between the Parties at Kasikili Island, even though they may have relevance in relation to the question whether Kasikili Island was occupied or cultivated. However, they are irrelevant because they were taken after 1914, the critical date as regards the subsequent practice of the Parties for purposes of interpreting the 1890 Anglo-German Agreement. Moreover, aerial photographs or satellite images cannot determine whether any occupation of Kasikili Island was carried out by Masubia people of the Eastern Caprivi or by natives or authorities of the Bechua-naland Protectorate.

H. Peaceful and Public Use of Kasikili/Sedudu Island by Masubia Tribesmen from Eastern Caprivi

79. The German Government first established an administrative presence in the Eastern Caprivi in February 1909. As Namibia acknowledged, "Until then, from the European colonial perspective, the Eastern Caprivi was 'a no-man's land', essentially outside the law" (Memorial of Namibia, Vol. I, p. 88, para. 222).

80. The German Governor in Windhoek, Bruno von Schuckmann, issued an ordinance on 16 October 1908 closing the territory to all Europeans without an official permit, "thus laying the legal basis for the exercise of administrative authority in the region". At the same time he appointed Hauptmann Kurt Streitwolf as Imperial Resident of the Caprivi who, at the head of a contingent of four German military officers and 14 African policemen, entered the Strip on 25 January 1909. Some days later, on 3 February, Hauptmann Streitwolf reached the southern bank of the Zambezi, opposite Sesheke, and established a new town, named Schuckmannsburg, where he set up his headquarters.
81. Namibia adds that on 4 May 1909 Hauptmann Streitwolf installed Chikamatondo at Schuckmannsburg "as the Masubia Chief, responsible to him for the governance of the area", Kasikili Island being "clearly within his jurisdiction". Thus Germany established the method of "indirect rule" and the native chiefs were constituted as an integral part of the machinery of the German administration. For this reason, Namibia concludes, the German rule of the Eastern Caprivi was carried out through Chikamatondo and the Masubia tribal organization (Memorial of Namibia, pp. 88-93, paras. 222-232).

82. Namibia maintains that the same method of "indirect rule" persisted after the creation of the mandate over the territory of South West [p1230] Africa. The Governor-General of the Union of South Africa delegated responsibility for the Caprivi to the British High Commissioner for South Africa, with effect from 1 January 1921 (Memorial of Namibia, Vol. V, Ann. 93, pp. 5-8), who exercised his authority through the Bechuanaland Protectorate (Memorial of Botswana, Annexes, Vol. Ill, Ann. 19, p. 257).

83. The British Administration lasted until 1929, when it was taken over directly by the Union of South Africa (Memorial of Namibia, Vol. V, Ann. 94, pp. 9-11; Memorial of Botswana, Annexes, Vol. Ill, Ann. 20, pp. 259-260.) During that period, British colonial officers also relied on the traditional authorities of the Masubia to carry out important governmental functions, such as administration of justice. This fact is evidenced by the reports written by Bechuanaland officials, acting as delegates of South Africa. Thus, all their Reports for the years 1927, 1928 and 1929 include the following paragraph:

"Each village has its Induna or Headman who has authority to adjudicate according to Native Law and Custom amongst his followers. He is generally assisted by the older men. If they do not agree or if the plaintiff or defendant is not satisfied, then the case it taken to the Chief s Kgotla.

The Chiefs Kgotla or Court is the principal one and its judgments are final except that provision is made under Proclamation No. 1 of 1919 for appeals against the judgments of native chiefs in the Bechuanaland Protectorate, in the first instance to a Court composed of the Assistant Commissioner or Magistrate of the district and of the chief, and in the event of their disagreeing, then the Resident Commissioner decides the matter in dispute. When members of a tribe are punished by their own courts the penalty is usually one or more head of cattle. The fines become the sole property of the chief, although he may give some of the cattle to his councillors." (Report of the Government of the Union of South Africa on South-West Africa for the Year 1927, Counter-Memorial of Botswana, Ann. 11, p. 123; Report of the Government of the Union of South Africa on South-West Africa for the Year 1928, Counter-Memorial of Botswana, Ann. 12, p. 108; Report of the Government of the Union of South Africa on South-West Africa for the Year 1929, paras. 458459, Counter-Memorial of Botswana, Ann. 13, p. 69, paras. 459-460.)

84. Botswana maintains that "it is implausible to suggest that the title could be generated by the agricultural activities of the Basubia"; that "there is simply no evidence that indirect rule conferred competence upon the Caprivi chiefs to make or unmake international boundaries"; and that Article VII of the 1890 Anglo-German Agreement provides that: [p1231]
"The two Powers engage that neither will interfere with any sphere of influence assigned to the other by Articles I to IV. One Power will not, in the sphere of the other, make acquisitions, conclude treaties, accept sovereign rights or protectorates, nor hinder the extensions of influence of the other.

It is understood that no Companies nor individuals subject to one Power can exercise sovereign rights in a sphere assigned to the other, except with the assent of the latter."

Therefore Botswana concludes that occupation of Kasikili Island by the Masubia of the Eastern Caprivi cannot create any Namibian title to Kasikili Island (Counter-Memorial of Botswana, Vol. 1, p. 12, para. 23.)

85. Nevertheless, Botswana admits:

"The Government of Botswana is willing to accept that, both in German-controlled territory and in Bechuanaland Protectorate, the authority of the traditional chiefs was subjected to a process of colonial approval. The chiefs thus became in a certain sense agents of the colonial administration on both sides of the River Chobe. But there is no evidence, and no evidence is offered, to the effect that the chiefs had authority to engage in title-generating activities. Both legally and historically this would be eccentric." (Counter-Memorial of Botswana, p. 278, para. 685.)

86. However, Namibia does not claim that Germany was engaged in title-creating activities on Kasikili Island through the Masubia tribal organization. In the opinion of Namibia the title remained the same, the 1890 Anglo-German Agreement. However, the boundary delimitation made by its Article III was not clear and needed interpretation. Therefore, Namibia relies on the subsequent practice of the Parties in order to interpret the existing title, i.e., the 1890 Anglo-German Agreement; no new title was created, the existing title was confirmed and interpreted by subsequent practice.

87. The evidence presented by Namibia demonstrates that Germany administered the Eastern Caprivi Zipfel through the Masubia Chiefs and their tribal organization. They exercised judicial functions and had authority to render judgments. Their positive acts of exercise of jurisdiction over Kasikili Island were frequent enough, taking into account that they were undertaken in areas sparsely populated and very remote from the centres of civilization, as the territory of South West Africa was described in Article 22, paragraph 6, of the League of Nations Covenant [p1232] (see para. 27 above). The Bechuanaland authorities never challenged such jurisdictional acts. For this reason, in my opinion, the Chiefs were agents of the colonial administration and their acts represent the subsequent practice of the Parties for purposes of the interpretation of the 1890 Anglo-German Agreement.

VII. CONCLUSION

88. The considerations set out in the foregoing sections lead to the conclusion that the Masubia of the Eastern Caprivi were the only tribesmen who occupied Kasikili/Sedudu Island, at least until 1914; that their occupation of Kasikili/Sedudu Island was peaceful and public; and that even Botswana acknowledged that their chiefs "became in a certain sense agents of the colonial administration" (see para. 85 above). Therefore, in my opinion, the subsequent practice of Germany and Great Britain reflected their understanding that Kasikili/Sedudu Island formed part of German South West Africa and that the southern channel of the Chobe River was the "main channel" referred to in Article III, paragraph 2, of the 1890 Anglo-German Agreement. No subsequent practice of the parties to the Treaty was possible during the First World War when British troops exercised de facto control over South West Africa. In 1920 the League of Nations confirmed the establishment of the Mandate over South West Africa. During the existence of the Mandate over South West Africa (Namibia) neither of the Parties to the 1890 Anglo-German Agreement had competence to recognize, either by express agreement or by subsequent practice, that the aforementioned "main channel" of the Chobe River was the northern channel and not the southern channel, since this new interpretation would have represented a modification of the territory submitted to the Mandate. Consequently, the original understanding was maintained and for this reason, in my opinion, Kasikili/ Sedudu Island forms part of Namibia and the southern channel of the Chobe River is the "main channel" referred to in Article III, paragraph 2, of the 1890 Anglo-German Agreement.

(Signed) Gonzalo Parra-Aranguren. [p1233]



DISSENTING OPINION OF JUDGE REZEK [Translation ]

1. I am sorry to find myself in complete disagreement with the majority. A particular source of regret is the gulf between the position taken by the Judgment and my own views concerning the principle of uti possidetis in the context of a colonial situation and the accession of peoples to independence. Over the course of my years of service on the Supreme Court of my own country, I learned that the majority is always right, and time has effaced any vestiges of doubt I entertained early on about the validity of that maxim. What follows, therefore, is not a plea in support of the losing side, particularly since both Parties had the benefit of impeccable representation in these proceedings, and their cases were argued thoroughly and tenaciously by their respective counsel. I could set out at length my support for the case put by Namibia, while paying tribute to the opinion of the majority of the Court's Members. However, I shall confine myself to indicating as succinctly as possible the substance of my dissent.

2. The Court correctly understood, in the light of Article III of the 1890 Anglo-German Treaty, that its task was not simply to determine the thalweg of the Chobe, but rather first of all to identify the point at which the main channel of the river bifurcates, and then to determine the thalweg of this channel — "im Thalweg des Hauptlaufes" — on the basis of the German version, which makes it clear, to readers of the English version, what is meant by the term "centre".

3. In identifying the main channel, where the two branches of the Chobe separate in order to encircle Kasikili/Sedudu Island, the Judgment appears to seek to attach more importance to geographical considerations, despite the attendant ambiguities. The northern channel has a greater mean depth and is therefore said to be more easily navigable than the southern channel, when the Chobe carries sufficient water to permit navigation at all. However, navigability is referred to in the abstract, since it is clear that, as far as actual traffic is concerned, the southern channel has always been more heavily used. It is there, moreover, that most of the Chobe's water resources are found, which should be [p1234] accessible to both Parties equally, in accordance with a basic principle of international law relating to river boundaries.

4. The northern channel is also said to have greater "visibility" in terms of its contours and banks, and is thus regarded, despite the lingering uncertainty about comparative volumes of water, as the more substantial of the two branches of the Chobe surrounding Kasikili/Sedudu. I ask myself whether this could have had any significance whatsoever to the colonial powers who negotiated the 1890 Treaty, or to their agents in the disputed region or to the indigenous communities over subsequent decades. This "visibility" is evidenced only by aerial photography, and was therefore non-existent at the time when the bilateral agreement was concluded and implemented.

5. I am unable to understand why the northern channel is considered to constitute the "natural prolongation" of the course of the Chobe when it reaches Kasikili/Sedudu Island. We are dealing here not with a railway or a road, but with a natural watercourse, which does not necessarily follow the most direct route. However, were I to accept that such morphological considerations should be taken into account, it would be difficult for me to say why the upstream prolongation should be given more importance than the downstream prolongation: indeed, when the two channels come together again, it is in fact the southern channel which appears to determine the orientation of the reunited watercourse.

6. The variability of the geographical aspect highlights the importance of the historical factor, when it comes to interpreting the 1890 Treaty correctly. It is likely that the parties used the conventional formulas for determination of the boundary line when it follows a watercourse on which islands are located, without according any particular attention to the features specific to the Kasikili/Sedudu area. There is no doubt, however, that the two powers became aware, with the passage of time, of the need to arrive at a proper interpretation of the Treaty in regard to the determination of the boundary at that precise location. Rather than seek to ascertain what the parties concerned meant by the words "main channel", since they probably had nothing special in mind, it fell to the Court to determine, with specific reference to the disputed area, what they read into those words during the decades following the conclusion of the 1890 Treaty.

7. All the same, it seems to me proven that access by river to the Zambezi was not the key objective for the parties to the 1890 Treaty, particularly for Germany. I accept that the main aim in the treaty negotiation was to delimit spheres of influence between the two powers. That aim was to be attained in the light of certain principles governing river boundaries, foremost among which is that of equality of access to the resources of a watercourse. An examination of the object and purpose of the 1890 Treaty also results in the identification of the southern channel as the main channel: [p1235]

"For, if the boundary were to be redrawn along the northern channel, Namibia would be entirely shut off from the southern channel — as it is, indeed, today because of the illegal military occupation of the Island. It would thereby be denied the use of the Chobe River where it actually serves the needs and interests of both riparian States. To continue this state of affairs by redrawing the boundary according to Botswana's claims would be incompatible with the object and purpose of the 1890 Treaty. It would also subvert the general principle of equitable and reasonable sharing of the resources of a boundary river enunciated by this Court in the case concerning the Gabcikovo-Nagymaros Project." (CR99/1, p. 66 (Delbrόck, for Namibia)).

8. Practice subsequent to the conclusion of the 1890 Treaty indicates as a whole that, as from the first decades after that date, the parties identified the southern channel as the main channel of the Chobe, where the latter reaches Kasikili/Sedudu Island. This is, moreover, acknowledged in the Judgment, which states that prior to 1947 the boundary "had until then been supposed to be located in the southern channel of the Chobe" (para. 62).
9. The agreements between the parties concerning the interpretation of the 1890 Treaty or the application of its rules contain information of varying import. As far as both Captain Eason's opinion and the 1948 Trollope-Redman report are concerned, I consider that Namibia is correct in its assertion that:

"The question whether the deeper channel is 'the main channel' within the meaning of the Treaty is an inference of law, as to which the officials have no particular expertise. If, as Namibia contends, the criterion of depth is not the correct one for identifying the main channel, then the reports of the officials are of no assistance in determining the main channel." (CR 99/11, p. 56 (Chayes).)

The Trollope-Dickinson agreement of 1951 confirmed the status quo ante, particularly as regards occupation of the Island by the Masubia, as well as the designation of the northern channel as "free for all". The parties "reserved their rights". I regarded this "gentlemen's agreement" as primarily indicative of the redundancy of declaring open the southern channel, which was understood to be the international boundary.

10. The map evidence is copious, but admittedly is not totally consistent. However, it is not just a matter of there being a numerical majority of maps on which the boundary at Kasikili/Sedudu is depicted as the southern channel; I was struck by the variety of sources and the temporal continuity displayed by these documents: the 1909 German map; the 1933 British map GSGS 3915; the 1949 South African map TSO 400/ 558; the United Nations map No. 3158, published in 1985. The most [p1236] impressive cartographic materials produced over that lengthy period date from the period of effective occupation of the Island and, in my view, confirm Namibia's rights.

11. There is scope, in principle, for the application in this case of the doctrines of prescription and acquiescence. Such application is fully in keeping with the provisions of the Special Agreement, as readily acknowledged.

These doctrines give expression to customary rules of international law, which are moreover of long standing, based on general principles such as "effectivite" and good faith, as well as on the dictates of reason, such as consideration of the passage of time and of failure to act. The Court has jurisdiction, under the terms of the Special Agreement, to give a ruling "on the basis of the Anglo-German Treaty of 1 July 1890 and the rules and principles of international law".

12. I consider that the occupation of the Island by the Masubia from the Caprivi side of the Chobe, an indisputable fact, dating back to a point in time close to the entry into force of the 1890 Treaty, and continuing at least until — and perhaps even beyond — a date close to that of Botswana's independence, can be considered to provide justification for acquisitive prescription. However, in my view interpretation of the 1890 Treaty in the light of history, and in a manner at least fully compatible with the hydromorphology of the disputed area, in itself provides sufficient grounds for recognition of the rights of the potential beneficiary of prescription, i.e., Namibia. Even if that were not so — in particular, if the interpretation of the Treaty effectively resulted in placing the main channel of the Chobe to the north of Kasikili/Sedudu — I would find myself able to take the view that the process of acquisitive prescription in favour of Namibia was completed even before the two former colonies became independent: a process involving all the attendant elements of prescription, including acquiescence by the other colonial power.

13. The Judgment does not deny that "links of allegiance may have existed between the Masubia and the Caprivi authorities" (para. 98). It does not, however, consider it "proven that the members of this tribe occupied the Island a litre de souverairi". To my mind, the animus of the occupation, its nature and its effects must be evaluated in the light of the surrounding circumstances and the period. What actions or indicia would have had to mark the presence of the Masubia on Kasikili/Sedudu Island in order for it to be recognized that they were there a litre de souverainl In my opinion, to deny that the indigenous occupation of the Island has any legal legitimacy and to take the view that this people lacked the necessary rights to live there a titre de souverain is an approach which would only make sense if we were still living in the first half of the century and the boundary dispute was not between the successors of Germany and Great Britain, but between the two powers themselves.

14. The Masubia were "private persons" according to the Judgment. Their allegiance did not, therefore, constitute sufficient title. It would perhaps have required the continued presence of agents of the German State [p1237] to justify either acquisitive prescription or the idea of conduct serving to confirm a particular interpretation of the 1890 Treaty. I nevertheless incline to the view that private persons provide perfect evidence of a peaceful occupation which deserves the protection of the law. Private persons — not agents of the State — wrote the history of uti possidetis in much of the American continent, where they altered the course of frontiers, frequently in defiance of the claims of the colonial powers.

15. I would readily admit that occupation by private persons would have no such legitimacy if the community in question was there under the authority of the other power or, at the very least, if it lived side by side with agents of the other power. In this case, even the presence on Kasikili/Sedudu Island of private persons bearing allegiance to Great Britain has not been confirmed with a minimum degree of permanency. Hence the relevance of the lesson drawn by the Permanent Court of International Justice in the case concerning the Legal Status of Eastern Greenland:

"It is impossible to read the records of the decisions in cases as to territorial sovereignty without observing that in many cases the tribunal has been satisfied with very little in the way of the actual exercise of sovereign rights, provided that the other State could not make out a superior claim. This is particularly true in the case of claims to sovereignty over areas in thinly populated or unsettled countries." (Judgment of 5 April 1933, P.C.I. J., Series A/B, No. 53, p. 46.)

16. With all due respect and not without regret, I dissociate myself from the majority of the Court. I would have reached the opposite conclusion in this case.

(Signed) Francisco Rezek.

 
     

 

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