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

4.6.5 Water quality data
None available.
4.6.6 Implications for water quality and quantity management
The impact of River Ranch, the only mining operation in the area (now closed), is likely to be restricted to a
minor contribution to siltation.
4.7 The Mzingwane sub-catchment
4.7.1 General description
4.7.1.1 Hydrology
This sub-catchment comprises Zones UZ1-UZ4, IN1-IN2, IK and NC of Area B (ZSG, 1984). The Mzingwane
(Umzingwani) River rises near Bulawayo and flows south to the Limpopo. Its major tributary is the Insiza
(Zones IN1-IN2). The Mzingwane, Ncema, Inyakuni and Insiza are all dammed in the Esigodini area (Zones
UZ1, NC, IK and IN1 respectively). The lower Insiza is dammed at Silabiuhwa (Zone IN2). The lower
Mzingwane is dammed at Zhove, near Mazunga in Zone UZ1.
4.7.1.2 Geology
See Figure 3.6 (ZZGS, 1999). The northern half of the sub-catchment is underlain by the Zimbabwe Craton:
Bulawayo Greenstone Belt, Gwanda Greenstone Belt, Filabusi Greenstone Belt and granitic terrain. The
southern half is underlain by Limpopo Belt gneisses, except for the area around Mazunga, which is underlain by
Karoo basalts.
4.7.1.3 Pedology, agriculture and land use
Soils in the sub-catchment can be divided into four groups:
• Moderately shallow, coarse-grained kaolinitic sands, derived from the granites;
• Very shallow to moderately shallow sandy loams, formed from gneisses;
• Very shallow to moderately shallow clays, formed from the Greenstone Belts; and
• Very shallow sands, derived from the basalts (DRSS, 1979).
From Gwanda northwards, the sub-catchment is in Natural Region IV, with low (under 650mm) and unreliable
rainfall, and poor soils. South of Gwanda is in Region V, with poor soils, rainfall under 600mm and in places
under 450mm (ZSG, 1997).
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