botswana/namibia - Cour international de Justice

223. The first of these is an absence of reference to the object and purpose of the Anglo-
German Agreement and the significance of the incorporation of the concept of the thalweg in
relation to navigability.
224. The second element involves the acceptance of the position adopted by the Government
of Botswana in the proceedings of the JTTE, that the identification of the 'main channel' of the
Chobe is 'in essence a question of fact' (Namibian Memorial, pp.46-7, paras. 121-22). This
position is, of course, based on the assumption that the assessment of the facts must
necessarily be based upon criteria which are compatible with the language of the Agreement
and with its object and purpose, that is to say, to produce an effective boundary allowing both
riparians equal access to the navigable channel: see the Botswana Memorial, pp.50-64, paras.
113-44.
225. The third element contained in the Namibian Memorial consists of reference to the
Awards in the Palena arbitration between Argentina and Chile in 1966 and the Laguna del
Desierto arbitration of 1994. Interesting though this jurisprudence may be, it appears to be
wholly irrelevant for present purposes. Both awards involved the interpretation of language of
a substantially different character, and in both cases the object and purpose of the instrument
the subject of interpretation did not relate to navigability.
226. In the Palena arbitration the task prescribed by the Special Agreement involved the
identification of the River Encuentro. The context was the duty of the Tribunal to answer the
question:
"To the extent, if any, that the course of the boundary between the territories of the parties in
the Sector between boundary posts 16 and 17 has remained unsettled since the 1902 Award,
what, on the proper interpretation and fulfilment of that Award, is the course of the boundary
in that Sector?" (Report of the Court of Arbitration, International Law Reports, Vol. 38, p.20
at p.23).
227. In the process of identification of the Encuentro, the Tribunal referred first of all to
historical evidence. Subsequently, and by way of confirmation, it referred to 'scientific
grounds'. The relevant passage is as follows:
"That this recognition of the Eastern Channel as the major channel was correct can be
confirmed on scientific grounds. In the Court's opinion the three principal criteria to be
applied in a problem of this kind are length, size of drainage area, and discharge, preferably in
terms of annual volume, though authorities differ as regards their relative importance (M.
Roche, Hydrologie de surface, Paris, 1963, p.152; Stephen B. Jones, Boundary-Making,
Washington, 1945, pp.129-130. These factors are moreover basic to the two American
methods of designating stream order; the Horton method applied by Chile, and the Strahler
method applied by Argentina. According to the Horton method, stream order is related to
number of streams, channel length and drainage area by simple geometrical relationships. As
regards the Strahler method, which Argentina considers the only objective method of
determining the order of importance of a river, Strahler states:
'Usefulness of the stream order system depends on the premise that, on the average, if a
sufficiently large sample is treated, order number is directly proportional to size of
contributing water-shed, to channel dimensions, and to stream discharge in that place in the