Geophysical investigations of alluvial aquifers in Zimbabwe

Geophysical investigations were carried out on shallow alluvial aquifers in conneetion with sand rivers in Zimbabwe. The primary methods used were OC resistivity imaging and ground penetrating radar (GPR). The investigated sites are situated on so called sand rivers. i.e. rivers with a seasonal surface flow. The strata of principal interest, for local water supply and subsistence irrigation purposes, are alluvial sands present in the active stream channel or beneath flood plains. The alluvium in the present stream channels consists of coarse grained sand, generally with a groundwater table within a couple of metres depth. These shallow aquifers are widespread in the dryer parts of Zimbabwe, as well as other countries in the region. Since resource development is possible with locally sustainable technology, it is of high potential value. Investigations were carried out at two sites on the Umzingwani River and one on the Shangani River with results that agree well, which is also supported by previous research (Owen 1989)'. The geophysical surveys have been presented in detail by Einarsson et al. (1994), Ekström et al. (1996) and Beekman and Liberg (1997).