OVERVIEW OF THE IMPACT OF MINING ON THE ... - IIED pubs

m 3 /day) water abstractions, and monitor the quantity and quality of all effluent discharges through a system of
effluent discharge permits or licences. Each licensed effluent discharger is required to carry out a routine
monitoring programme of the flow and quality of their effluent and supply this to DWAF. The Department then
conducts a randomised series of audit samples to check the veracity of the effluent returns submitted by each
discharger. Each industry and mining operation in Phalaborwa regularly monitors its effluent discharge quality
and reports the results to the Department.
5.7.5 Water quality data
The water quality data for the lower Selati River shown in Table 5.13 are representative of the typical water
quality of this reach during the dry months of the year. During the summer months when “normal” runoff
patterns resume, the water quality improves dramatically. Nevertheless, aquatic ecosystems are exposed to
greatest stress during the dry winter months when river flows are lowest; at this time of year, the poor quality
water in the Selati River can b expected to have the greatest impact on water in the lower Olifants River.
5.7.6 Implications for water quality and quantity management
The “new” inflows of effluents from mining operations into the lower reaches of the Selati River has a positive
effect in that, despite its poor quality, this water supplements the flows in the lower Olifants River. However, the
resultant water quality of the lower Olifants River is not considered to be suitable for protection of aquatic
ecosystems (DWAF, 1996) and is also unfit for human consumption at the Olifants and Balule rest camps in the
Kruger National Park. In addition, the quality of water entering the Massingir Dam in Mozambique would also
be unsuitable for irrigation of sensitive crops and may contravene the requirements of international agreements
between South Africa and Mozambique. This aspect needs to be checked very carefully and, if verified, a
concerted effort should be made to improve the quality of mining effluents discharged into the lower reaches of
the Selati River.
5.8 The Middle and Great Letaba sub-catchment
5.8.1 General description
5.8.1.1 Hydrology
This sub-catchment consists of the area drained by the Great and Middle Letaba rivers and their main
(perennial) tributaries, the Klein Letaba, Molatotsi, Nsama, Politsi, Letsitele, Thabina rivers, as well as the
episodically flowing tributaries, the Ngwenyeni, Shipikani and Tsende rivers (Figure 4.2). The tributaries of the
Great and Middle Letaba rise on the high rainfall northern slopes of the east-west trending Drakensberg
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