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Report No 678-F-001
METSI CONSULTANTS: SUMMARY OF MAIN FINDINGS FOR PHASE 1 DEVELOPMENT
MOHALE DAM
Mohale's Hoek
Senqu
6
Quthing
KATSE DAM
7
Senqunyane
8
Lesobeng
Malibamatso
2
Thaba Tseka
5
MASOKU WEIR
1
Senqu
3
4
Matsoku
Qacha's Nek
LEVEL OF IMPACT:
NOT ASSESSED:
Negligible:
Low:
Moderate:
Severe:
Critically severe:
Position of IFR Site
North
0 20 40
Kilometres
Figure 7.1 Broad summary of the likely severity of the biophysical impacts downstream of the LHWP Phase 1
dams under the Design Limitation Scenario.
7.3. SOCIAL IMPACTS
The social impacts associated with the Design Limitation Scenario can be summarised as generally moderate,
except for Reaches 4, 5 and 6, far away from the dams, where they are low. In simple terms this means that
although there would be a reduction in the river resources used by the PAR, this reduction would tend to be less
than 50% for most of the resources used. The notable exceptions to this are fish populations, which are expected
to decline dramatically in the reaches immediately downstream of the dams. There are, however, concerns that, if
the resources that are lost are not compensated for, then the potential for extensive over-utilisation of the
remaining resources would be great, thus leading to their eventual decrease below harvestable levels.
For public health, risk for diarrhoeal diseases is expected to remain moderate along all reaches, except 1, 2 and
3, where it is predicted to become severe. The nutritional risk remains at baseline level throughout, as is the case
for other pathologies, except for a slight increase in the risk of schistosomiasis in reaches close to the dams. It is
likely that the rivers would not present any more of a health risk than they do at present for much of the time, but
there would be occasions when they represent a serious health risk along Reaches 1, 2 and 3. It is difficult to
predict the frequency of these occasions, other than to say that they would be more often than at present, but
probably less often than under the Treaty Scenario. An example could be in summer when temperatures are
high, runoff from rainfall also high (faeces are flushed off the surrounding areas into rivers during times of rain)
but the flow in the rivers is considerably lower than natural, and thus the dilution would be lower. Such water
would have a higher than present level of faecal contaminants and parasites such as Giardia, with a concomitant
increased health risk for those drinking or bathing in the water.
As with the Treaty Scenario, the increase in the incidence of livestock diseases and/or injuries under the Design
Limitation Scenario remains low. However, a moderate increase in nuisance species such as Simulium nigritarse,
a pest of poultry, is predicted.
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