Kasikili/Sedudu Island (Botswana/Namibia)

On 29 May 1996, the Government of Botswana and the Government of Namibia notified jointly to the Registrar of the Court a Special Agreement which had been signed between them on 15 February 1996 and had entered into force on 15 May 1996, for the submission to the Court of the dispute existing between them concerning the boundary around Kasikili/Sedudu Island and the legal status of that island. The Special Agreement referred to a Treaty between Great Britain and Germany concerning the respective spheres of influence of the two countries, signed on 1 July 1890, and to the appointment on 24 May 1992 of a Joint Team of Technical Experts to determine the boundary between Namibia and Botswana around Kasikili/Sedudu Island on the basis of that Treaty and of the applicable principles of international law. Unable to reach a conclusion on the question submitted to it, the Joint Team of Technical Experts recommended recourse to a peaceful settlement of the dispute on the basis of the applicable rules and principles of international law. At a Summit Meeting held in Harare, Zimbabwe, on 15 February 1995, the Presidents of the two States agreed to submit the dispute to the Court.

Taking account of the relevant provisions of the Special Agreement, the Court, by an Order dated 24 June 1996, fixed time-limits for the filing, by each of the Parties, of a Memorial and a Counter-Memorial. Those pleadings were duly filed within the time-limits fixed.

The Court, in view of the agreement between the Parties, also authorized the filing of a Reply by each Party. The Replies were duly filed within the time-limits so prescribed.

In its Judgment of 13 December 1999, the Court began by stating that the island in question, which in Namibia is known as “Kasikili”, and in Botswana as “Sedudu”, is approximately 3.5 sq km in area, that it is located in the Chobe River, which divides around it to the north and south, and that it is subject to flooding of several months’ duration, beginning around March. It briefly outlined the historical context of the dispute, then examined the text of the 1890 Treaty, which, in respect of the region concerned, located the dividing line between the spheres of influence of Great Britain and Germany in the “main channel” of the River Chobe. In the Court’s opinion, the real dispute between the Parties concerned the location of that main channel, Botswana contending that it was the channel running north of Kasikili/Sedudu Island and Namibia the channel running south of the island. Since the Treaty did not define the notion of “main channel”, the Court itself proceeded to determine which was the main channel of the Chobe River around the Island. In order to do so, it took into consideration, inter alia, the depth and the width of the channel, the flow (i.e., the volume of water carried), the bed profile configuration and the navigability of the channel. After considering the figures submitted by the Parties, as well as surveys carried out on the ground at different periods, the Court concluded that “the northern channel of the River Chobe around Kasikili/Sedudu Island must be regarded as its main channel”. Having invoked the object and purpose of the 1890 Treaty and its travaux préparatoires, the Court examined at length the subsequent practice of the parties to the Treaty. The Court found that that practice did not result in any agreement between them regarding the interpretation of the Treaty or the application of its provisions. The Court further stated that it could not draw conclusions from the cartographic material “in view of the absence of any map officially reflecting the intentions of the parties to the 1890 Treaty” and in the light of “the uncertainty and inconsistency” of the maps submitted by the Parties to the dispute. It finally considered Namibia’s alternative argument that it and its predecessors had prescriptive titles to Kasikili/Sedudu Island by virtue of the exercise of sovereign jurisdiction over it since the beginning of the century, with the full knowledge and acceptance of the authorities of Botswana and its predecessors. The Court found that, while the Masubia of the Caprivi Strip (territory belonging to Namibia) did indeed use the island for many years, they did so intermittently, according to the seasons and for exclusively agricultural purposes, without it being established that they occupied the island à titre de souverain, i.e., that they were exercising functions of State authority there on behalf of the Caprivi authorities. The Court therefore rejected that argument. After concluding that the boundary between Botswana and Namibia around Kasikili/Sedudu Island followed the line of deepest soundings in the northern channel of the Chobe and that the island formed part of the territory of Botswana, the Court recalled that, under the terms of an agreement concluded in May 1992 (the “Kasane Communiqué”), the Parties had undertaken to one another that there should be unimpeded navigation for craft of their nationals and flags in the channels around the Island.