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

3.26.6 Implications for water quality and quantity management
There is no evidence to suggest that mining operations have had an influence on water quality in the area.
3.27 The Sengwa sub-catchment
3.27.1 General description
3.27.1.1 Hydrology
This is Zone Z3 of Area A (ZSG, 1984). The sub-catchment comprises the valley of the Sengwa River and its
tributaries, the Busi and the Rutope (Lutope) (Figure 3.2). None of the rivers are perennial. There are some
small wetlands associated with the Upper Busi River.
3.27.1.2 Geology
See Figure 3.6 (ZGS, 1999). The geology consists mainly of Karoo Supergroup sediments, capped on the
Mafungabusi (Mapfungautse) Plateau by Karoo basalt, Gokwe Formation sediments and Kalahari Sands.
3.27.1.3 Pedology, agriculture and land use
Soils in the sub-catchment can be divided into four groups:
• Kalahari Sands;
• Moderately deep sandy soils derived from Karoo sediments;
• Moderately deep kaolinitic sandy to loamy sand soils derived from Sijarira Group sediments; and
• A few locally developed salty vertisols (DRSS, 1979).
The sub-catchment lies in three Natural Regions: Region V in the Zambezi Valley: low and erratic rainfall: below
650mm; Region IV in the middle Sengwa Valley: fairly low rainfall of 450mm to 650mm per annum; Region III on
the Mafungabusi Plateau and in the Rutope valley: higher rainfall and deeper soils (ZSG, 1997; Surveyor
General and AGRITEX, 1998).
clxiv