EIA-REP-325d-12 _BB_ - 201.09.14.pdf - SAHRA

The Vaal River in the vicinity of the Witpuntspruit is a perennial river. The flow in the Vaal River shows typical
seasonal trends with dry weather flows being significantly less than wet weather flows. The 50 year flood peak
for the Witpuntspruit at the N2 bridge is 277m 3 /s and the 100 year flood peak is 379m 3 /s.
Water quality data was measured by Environmental Assurance at the upstream and downstream ends of the
proposed opencast mine. The water quality in the Vaal River upstream of the mine deteriorates from the origin of
the river to the N2 crossing. At the N17 crossing, the water quality is still relatively good, typical coal mining
influences are absent. The results indicate high organic concentrations possibly as a result of sewage pollution
and other domestic influences.
At the N2 bridge the Vaal River shows signs of pollution from coal mining activities. These include the pH which
has dropped significantly, while the SO4 is elevated. Nutrient pollution levels appear to be similar and possibly
even improved compared to the upstream samples.
At the N11 bridge the Vaal River shows a general improvement. This is due to the tributaries contributing clean
water to the Vaal River upstream of the N11 bridge. The tributaries drain a mainly agricultural catchment
southeast of the Grootdraai Dam catchment.
Water quality in the Witpuntspruit is not good when compared with the Vaal River. The water quality shows
definite signs of domestic and coal related pollution. Ermelo’s sewage treatment works discharges into the Klein
Drinkwaterspruit. The sewage works is therefore not responsible for adding nutrients to the Witpuntspruit,
however the WWTW at Usutu discharges into a tributary of the Witpuntspruit and this may result in the high
nutrient levels.
The water downstream of the site in the Witpuntspruit is used for livestock watering. The Witpuntspruit flows into
the Vaal River downstream of this confluence; water is mainly used for irrigation, livestock watering and
consumption.
EIA-REP-325d-11
October 2012
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