botswana/namibia - Cour international de Justice

Memorial, Vol.6,part 2) but merely a sub-channel into which flood waters flow when backing
upstream.
IV. The width of the northern channel is consistently greater than the southern channel
395. Comparison of the width of the northern channel, which is never less than 140 metres
and on average is 200 metres or so in the northern sector, compared with that of the southern
channel 60 to 80 metres at its western entry, widening in the lagoon sector to 200 metres and
at its eastern exit, but averaging 50 metres or less overall, indicates the difference. Even at its
widest the southern channel never exceeds the width of the northern channel, even at times of
high water which is visible on the June 1997 photograph at page 187.
V. Greater depth of water is indicated in the northern channel
396. This is true in respect of all the photographs and in the May 1972 photograph the
southern channel is dry for half its length.
VI. Deposit of sediment
397. The deposit of sediment in the western sector of the northern channel at the point marked
B indicates the zone of highest current velocity.
(iii) Detailed examination and interpretation of the photographs
398. Each aerial photograph will now be examined and interpreted. To give an indication of
the extent of any floods, the average annual mean flows in the Zambezi River at Victoria Falls
are set out for each hydrological year before and after the October of the year given as the
date on which the photograph was taken. The average flow between the years 1907 and 1993
is 1056 cubic metres per second, the highest 2328 in 1957 and the lowest 449 in 1914.
The 1925 Photograph (Scale 1:10,000). Average mean flows 1018 m3 (1924); 1136 m3
(1925). Reproduced with labels at page 161.
399. This photograph was taken by the Du Toit expedition of 1925 (the Kalahari
Reconnaissance) and must surely rank as amongst the oldest air photography ever taken in
Africa. The photograph is a composite mosaic composed of several photographs which have
been cut out and then fitted to the complete image of the Island and its immediate
surroundings. Although, as is to be expected, image quality and contrast is poor and variable,
a good deal of information can be obtained from careful examination.
400. All the common features, particularly IV and V (greater width of channel and deposit of
sediment) are clearly demonstrated. At no point, except in the lagoon and at its eastern exit,
does the width of the southern channel equal that of the northern channel which throughout
measures almost double the width. This is a clear indication that a larger volume of water is
flowing through the western and northern channel, and hence is the main channel.
401. The large deposit of sediment accreted to the left bank of the northern channel at point B
indicates the zone of the highest current velocity.