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9.3.4 Scenario 4. Wise use plus upstream abstraction
Extreme hydrological development upstream (Angola dams, irrigation in Namibia, and delta
abstraction)
This scenario is based on the wise use scenario plus upstream water resources development as
described in Scanagri et al. (December 2005). The water resources developments are as follows:
• Development of ten dams for hydropower in Angola, changing the distribution of flow and
altering sedimentation into the delta;
• Irrigated area of 54 500 ha in Angola and 7500 ha Namibia, creating an irrigation demand of
15 000 m 3 /ha/annum;
• Abstractions of surface water in the Delta for domestic supply, livestock, small scale irrigation
and construction. The modelled amount is a total abstraction of 68 000 m 3 /day, as the
projected demand in 2025 (current use is about 46 540 m3/day; Scanagri et al. 2005).
Scanagri et al. (2005) predicted the impacts on flow based on the above scenarios, and how these
would affect the areas of five types of flood area ranging from permanently flooded to rarely flooded
areas (Figure 9-3). Note that the rarely flooded area includes large parts of what is woodland today.
The delta wetland area can be considered as the first four areas, but it should be noted that molapos
and some minor wetlands and floodplain areas are situated in the fifth zone.
Figure 9-3 Different categories of flooding area in the Okavango Delta (Scanagri et al. 2005)
We used the average results over the three periods predicted by Scanagri et al. (2005). Under the
abstraction scenario, the delta proper is reduced in area by 10%. This reduction is fairly uniform
across the different flood zones (Figure 9-4).
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