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

The growing water shortages in Botswana and Zimbabwe have prompted several investigations of the feasibility
of transferring water from the Zambezi River to urban demand centres in these countries. South Africa (not a
Zambezi basin state) has also considered the feasibility of entering into an agreement with the Zambezi basin
states to withdraw water from the Zambezi and transfer it via pipeline to the Witwatersrand in South Africa
(Ashton, 2000). Whilst none of these water transfers have taken place, they do indicate the growing tension in
southern Africa around looming water shortages driven by population growth and development. The picture is
made somewhat more uncertain by the very real possibility that global climate changes will also have an
adverse effect on water availability in southern Africa (Ashton, 2000).
Throughout the length of the Zambezi River, water quality is generally very good and the water is entirely fit for
all designated uses. However, several communities continue to discharge untreated or partially treated
domestic effluent into the river (e.g. the towns of Livingstone in Zambia and Victoria Falls in Zimbabwe). Whilst
sufficient dilution remains and the river flows are turbulent, this practice is unlikely to have long-term or largescale
detrimental effects. However, as effluent quantities increase and river flows decline, whilst demands for
water increase, it is inevitable that water quality problems will occur. This problem is likely to become more
acute further downstream, where several more towns (e.g. Siavonga, Kariba, Chirundu and Tete) rely on water
abstracted directly from the Zambezi River and who also discharge their effluent (treated and untreated) directly
into the Zambezi River.
In addition to water abstracted for domestic use, large volumes of water are also withdrawn for irrigation; for
example: the Gwembi Irrigation Project on Lake Kariba, The Chaiwa Irrigation Project downstream of the Kafue-
Zambezi confluence and the Sena Sugar Estate on the lower Zambezi in Mozambique. Similar irrigation
schemes for sugar cane also operate on the Shire River in Malawi (e.g. Sucoma Sugar Estate) and the Kafue
River in Zambia (e.g. the Nakambala Sugar Estate). In addition, large citrus estates such as the Mazowe Citrus
Estate in Zimbabwe also withdraw substantial volumes of water (Chenje, 2000). Most small-scale farmers rely
either on red-fed agriculture or on water drawn from shallow wells or nearby watercourse (Chenje, 2000).
3.1.5 Water management systems and institutions
Each of the basin states has their own water management systems and segments their respective territories
into Water Management Units. These divisions are normally in the form of sub-catchments, though some of the
larger sub-catchments are further sub-divided (e.g. the Kafue and Luangwa in Zambia; the Shire in Malawi).
The formal constitution of catchment councils or catchment management agencies has only taken place in
Zimbabwe. In the other basin states, water management is undertaken by central Government or is delegated
to Provincial Departments.
In Zimbabwe, the Zimbabwe National water Authority (ZINWA) segments the Zimbabwean sector of the
Zambezi Catchment into three Catchment Councils: Gwayi, Sanyati and Mazowe. These correspond to
Hydrological Zones A, C and D, respectively (ZSG, 1984). The Zimbabwe portion of the catchment is divided
into a series of sub-catchments for the purposes of this study, as shown in Figure 3.2. Water quality data is
available from a number of ZINWA sampling points in Zimbabwe (Figure 3.3). The only information that could
be obtained for the other basin states consisted of a few water quality data for the Kafue sub-catchment in
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