The Council for Geoscience has a corporate responsibility in rural development projects as part of the South African government initiative in food and water security. Geophysical surveys were carried out at Elizabeth Conradie School in Kimberley, Northern Cape Province South Africa aimed on siting production boreholes to supply the school with water. Traditional geophysical techniques including magnetic, electromagnetic and resistivity were used to locate groundwater bearing structures. The magnetic method was used to locate intrusive magnetic bodies (i.e. Dolerites), while electromagnetic and resistivity were used to map conductivity and resistivity distribution associated with the subsurface geology.
The magnetic method delineated possible groundwater bearing structures which may be related to dolerite dykes and sills. The electromagnetic method appears to have identified shallow fresh dolerite sill. The resistivity method was good in identifying areas of low resistivity which might be related to fractures and/or faults. The high resistivity values might be related to dolerite dykes or sill.
The results of the study showed that geophysical methods are useful non-intrusive tools for mapping groundwater resource. The 1:250 000 scale geological reconnaissance map used to constrain the geophysical interpretation is at a bigger scale when compared to the geophysical interpretation resolution. Considering this and also the ambiguity and none uniqueness in geophysical interpretation, results need to be consolidated by a local scale hydrogeological mapping and drilling results.