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

Throughout the length of the Olifants River and its tributaries, water quality is considered to be generally good
and the water is usually fit for most designated uses. However, several areas in the central and lower reaches
of the basin experience serious water quality problems due to increasing salinity, making the water less suitable
for irrigation purposes and for domestic use. In addition, most cities, towns and smaller communities discharge
untreated or partially treated domestic and industrial effluent into the various rivers (e.g. the cities and towns of
the Mpumalanga Highveld). As long as the waste material is innocuous and there is sufficient dilution, this
practice does not have long-term or large-scale detrimental effects. However, with increasing quantities of
effluent and declining river flows due to escalating demands for water, water quality problems now occur more
frequently. Water quality problems caused by seepages and effluent discharge tend to become more acute
further downstream, as more and more towns contribute their effluent to the total river flow and evaporative
concentration accentuates the effects of rising salinity and increasing eutrophication. Seepage losses or
discharges of effluent containing potentially toxic compounds compound these problems.
In some sub-catchments where the rivers are normally seasonal and only flow during the wet summer months,
effluent discharges and seepage from mining operations have transformed the river into a perennially flowing
system. In the case of a river such as the Selati, effluent discharges and seepage now comprises the entire dry
season flow of this river and often equal the flow in the lower Olifants River itself.
In addition to water abstracted for domestic use, large volumes of water are also withdrawn for irrigation; for
example: the extensive irrigation areas along the main stem of the Olifants River and many of its major
perennial tributaries. Most small-scale farmers have to rely either on red-fed agriculture or on water drawn from
shallow wells or nearby watercourses. Overall, the competition for the limited water resources available is likely
to become more intense in future.
The Olifants basin has been divided into a series of sub-catchments for the purposes of this study; these subcatchments
are shown in Figures 4.2 and 4.3.
5.1.5 Water management systems and institutions
Both South Africa and Mozambique have their own water management systems and segments their respective
territories into Water Management Units or Water Management Areas. These divisions are normally in the form
of sub-catchments, though some of the larger sub-catchments may be further sub-divided.
In the South African sector of the Olifants basin, the South African Department of Water Affairs and Forestry
(DWAF) is the authority responsible for all aspects of water resource and water quality management. The
Department delegates the responsibility of water supply to communities and industries to Local Authorities or
Water Utilities wherever possible. In future, the Department will constitute formal Catchment Management
Agencies to deal with all aspects of water resource management and water supply. In Mozambique, the
equivalent functions are fulfilled by the Mozambique Department of Water.
The SADC Protocol on Shared Watercourse Systems provides an important legislative instrument that promotes
regional co-operation and collaboration amongst all SADC states. However, unequal institutional and
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