botswana/namibia - Cour international de Justice

402. The marked stand of big hardwood trees on the northern spit of the Island shows that
even in 1925 the trees were already well established. Although dark, it is possible to see that
Sedudu Valley, which enters the southern channel at the bifurcation zone marked B, is
covered by a dense stand of bush and large trees. This dense tree cover would have the effect
of stabilising the soil and minimising erosion during stormwater run-off. There is no
permanent stream in this valley which serves only as a conduit for rainwater run-off.
The 1943 photograph (Scale 1:10,000 approx.) Average mean flows 714 m3 (1942); 956 m3
(1943). Reproduced with labels at page 163.
403. The bright reflexion along the western and northern channels is caused by the sun angle
at the moment of exposure and is a common feature of air photography. The outline of the
channels, physical features and relative sizes are almost identical to the previous photograph.
Reed beds are clearly visible above the water level almost blocking the southern channel at its
narrowest point to the left of C. This indicates that the water at this point is very shallow.
Reeds are also evident to the left of the bifurcation zone at B growing on sand banks just
under the water surface. Cross-sections 19 and 19A of the 1985 Joint Survey established
depths at this point of less than half a metre. The sediment spit at A remains unchanged,
proving the absence of current in the southern channel. Similarly the spit on the south side of
the entrance to the southern channel at B remains; it has not been eroded nor has the entrance
to the channel widened. The presence of reeds and sandbanks across the western entrance to
the southern channel is clearly visible in the photographs taken in September 1997
(photograph opposite page 153).
G26 - 1925 aerial photograph with labels
404. The 'boundary' line referred to by Professor Alexander (para 388 above) is observable. It
is clearly evident from this photograph that it is a subchannel dividing the higher western half
from the lower eastern sector of the island and linked to the pronounced inlet in the eastern
sector of the southern channel. The surface texture is no different on either side of this line.
The 1947 Photograph (Scale approx. 1:10,000) Average mean flows 1261 m3 (1946); 1712
m3 1947). Reproduced opposite page 167.
405. The image on this photograph, when compared with the image on the 1925 and 1943
photographs, shows no detectable changes in shape, indicating that no erosion or deposition of
silt has taken place in the twenty-two year period covering the photography. There is no sign
of erosion on the western bank of the sediment spit at A, again indicating that current along
this section of the channel is minimal.
406. The four sediment bars are clearly visible in the same size, shape and position as shown
by Professor Alexander in the 1981 photograph at diagram 5 on Sheet 18 of Volume VI, Part
2, of the Namibian Memorial. This clearly disproves his claim that they shift and provide
evidence that the southern is the active channel.
407. Whilst the northern channel in both its sectors maintains a constant size on the
photographs, the size of the southern channel varies considerably over the seasons, indicating
that the northern channel is the least affected by seasonal variations in water-levels. At the
point marked D the southern channel is effectively closed by silt indicating that at times of
low water it is not always navigable throughout its full length. At times of low water the