botswana/namibia - Cour international de Justice

"Substantially all of the annual flow of the Chobe River is carried to the confluence with the
Zambezi by the southern channel." (Namibian Memorial, p.50, para.133.)
298. This constitutes a serious distortion of the facts. The southern channel is a backwater for
the greater part of the year: see paragraph 279 above. Article III of the Anglo-German
Agreement of 1890 speaks of a boundary line which "descends" the centre of the main
channel of the Chobe, and hence envisages downstream flow. Even if, as is accepted, some
backflow from the Chobe occurs by the action of the Kasai cross-channel, it is incorrect
therefore to refer to upstream flow, or non-directional flow, in ascertaining the main channel.
(v) The misrepresentation that the northern channel does not exist as a channel of the
Chobe River
299. Again the Namibian Memorial asserts:-
"Thus, the northern channel can hardly be considered a channel of the Chobe River at all. In
the dry season it is stagnant, in the flood season it is refilled by the floodwaters of the
Zambezi, but no water flows through it downstream in the Chobe in either season. As
Professor Alexander says, it is, in effect, a relict channel of the Zambezi floodplain."
(Namibian Memorial, p.7,para.23.)
300. This is not correct. The longitudinal slope of the bed is steeper in the northern channel
than the southern. The depths surveyed in the 1985 Joint Survey were used together with
distances along the middle of the channels surveyed to plot the bed profiles of the two
branches of the Chobe River in the vicinity of Kasikili/Sedudu Island (Figure 9 in Professor
Sefe's Second Opinion, reproduced at page 129). It can be seen that the bed profile of the
northern channel is steeper and more irregular over a comparable distance. Velocity is bound
to be higher in the northern channel than the southern. Given that the northern channel is
deeper and wider on the average, flow will be higher than in the southern channel.
(vi) The misrepresentation that black soil in the southern channel is indicative of flow
301. The Namibian Memorial phrases this argument as follows:-
"When the River reaches Kasikili Island, the black soil continues to appear in the bed of the
southern channel , but not in the northern channel. The material of the bed and banks of the
northern channel does not consist of recently deposited sediment from the Chobe River, but
rather floodwater deposits emanating from the Zambezi River over a long period of time
similar to the material that constitutes other parts of the floodplain." (Namibian Memorial,
p.54,para.150.)
302. This misrepresents the position both as to the distribution of black soil and its relevance
to determination of flow levels. As both the Second Opinion of Professor Sefe [Appendix 2]
and the Sedimentological Report (Appendix 3 of the Botswana Counter-Memorial) show,
black soil of basaltic origin is found throughout the Island and supports the view that there is
no great difference in distribution of basaltic deposits in the northern and southern channel,
such deposits being widely distributed.
(vii) The misrepresentation that to qualify as the main channel the northern channel
must show evidence of erosion